


Case Studies in Demon Mating Habits

by KorrinBelle



Category: Ao no Exorcist | Blue Exorcist
Genre: Accidental Marriage, Anal Sex, Angst, Biting, Bloodplay, Developing Relationship, Dubious Consent, If I'm being generous, Licking, M/M, Non-Consensual Drug Use, Probably more like, Rape/Non-con Elements, Recovery, Rimming, Sex Pollen, Teeth, sort of
Language: English
Status: In-Progress
Published: 2016-03-28
Updated: 2016-08-26
Packaged: 2018-05-29 14:34:57
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 9
Words: 23,226
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6380146
Author URL: https://archiveofourown.org/users/KorrinBelle/pseuds/KorrinBelle
Summary: <blockquote class="userstuff">
              <p>A mission gone wrong lands Ryuuji at the mercy of Rin's natural demonic instincts and both boys are shocked to find themselves locked in to a more permanent "arrangement". Will they be able to find a cure for their condition or will they be able to make things work despite such a black cloud hanging over the start of their relationship?</p>
            </blockquote>





	1. Chapter 1

            “I’m bored,” Rin said as he pushed aside branches and weeds, making a path through the woods. He glanced aimlessly from side to side, looking for signs of anything out of place.

            “Could you be quiet?” Ryuuji hissed, his annoyance bleeding through even though he spoke in hushed tones, “It could hear you.”

            “We’ve been out here for hours,” Rin said, not bothering to lower his voice and ignoring Ryuuji’s order entirely, “We haven’t seen a single sign of it, not footprints or-”

            Ryuuji grabbed him, clamping his hand over Rin’s mouth and glaring down at him.

            “We don’t even know what _it_ is yet, so for the love of God, shut your mouth and pay attention to what we’re doing. I don’t want to be out here any longer than you do, so let’s get this over with as quick as possible.”

            Rin glared back at him, snorting in annoyance, a short puff of warm air washing over Ryuuji’s hand, but then his eyes widened and he jerked away from Ryuuji’s grip.

            “I smell some–”

            They were hit with a blast of damp perfumed air—a sickly sweet, cloying scent—and spun to see their quarry emerging from the underbrush. It was vaguely humanoid in shape. Tall, and gangly, its long limbs were covered in glyphs, like scars that had been carved directly in to its flesh; some old, some new. Those same limbs were already working their way through some sort of complicated magical gesture.

            “Kill it!” Ryuuji shouted, “Before it finishes!”

            Rin didn’t need to be told twice. A dark gap in space was already forming between them and the demon. It was only an inch big but rapidly growing, and coal tars were beginning to pour out of it.

            Rin drew his sword, his flames bursting to life as he charged the creature, ignoring the coal tars as they began to swarm him, clinging to him like small burs. A clawed hand was emerging from the portal. Whatever the hand was attached to was too big to climb through, but that wouldn’t last long as the portal continued to grow. Rin dodged around the portal and the monster stepped back, but not quick enough and Rin cleaved it in two. Its garbled shriek of pain rang out and was abruptly silenced. The portal snapped closed with a loud crack and a severed hand fell to the grass, oozing black putrid blood and causing the grass around the hand to sizzle and blacken.

            Rin swatted at the coal tars still clinging to him, trying to brush them away, but there were too many and they ignored his attempts, even clinging to his hands as he tried to remove them, like fluffs of Styrofoam drawn by static. Even his flames weren’t doing anything to deter them.

            No matter what he did he couldn’t remove them and he was beginning to feel hot, his blood running thick. Rin turned to see Ryuuji in much the same state, looking like he was wearing a large pulsing fur vest as the coal tars clung to him. In spite of that, Ryuuji stood calmly, his hands held in front of him as he chanted, and when he finished the quick verse the coal tars evaporated like wisps of smoke.

            “The hell was that?” Rin asked. His hands were shaking as he fumbled Kurikara back in to its scabbard.

            “That,” said Ryuuji, “was a Gate Keeper. They’re not physically strong by themselves, but they can open small temporary gates to Gehenna and they attract other demons using pheromones.”

            “T-That the stuff it hit us with?” Rin asked. He stared down at his hands, struggling to focus on them, his head feeling heavy and clouded. “Izzit dangerous?”

            “No,” Ryuuji said. “It shouldn’t have any effect on humans.” He moved over to the severed hand, inspecting it carefully where it lay in the grass, not daring to touch it not knowing what kind of demon it had come from. “Rin, you need to burn this. We can’t leave it lying around.”

            “S-gu…ro.”

            Ryuuji looked up at him then, finally noting the distressed tone of Rin’s voice and the fact that he was having difficulty speaking, and froze. Rin’s pupils were so dilated they were practically consuming his irises, and he was panting, his face flushed and covered in a light sheen of sweat.

            Oh, shit. That wasn’t good. Ryuuji hadn’t even considered the possible effects the pheromones would have on Rin.

            “Okumura? Are you okay?”

            Rin didn’t answer, locking his eyes on Ryuuji instead, his mouth parted, fangs visible. He was breathing much too heavy for how short the fight had been.

            Ryuuji felt suddenly vulnerable, sensing the change in his friend, but he resisted the urge to run. When facing a wild animal it was the last thing you wanted to do, because it set off chase instincts, not that Rin was an animal, but at this point Ryuuji still had no clue what Rin would do.

            The half demon was circling him, sniffing the air as he made a slow approach, closing the distance between them.

            Ryuuji raised his hands—to defend himself or make himself look bigger? He had no clue. Standard animal survival tactics probably didn’t apply to demons anyways, but what did he know about surviving attacks instigated by Gate Keeper pheromones? Not much. One of the reasons they didn’t know what to expect walking in to this mission was because Gate Keepers were practically impossible to identify by their victims since they didn’t do their own fighting. Bodies mutilated by a half dozen different demons didn’t provide much in the way of usable information either, but this was just one demon, and not just _any_ demon, but his friend. His friend who happened to be the son of the most powerful demon in the known universe.

            Deep down Ryuuji wanted to believe that Rin wouldn’t hurt him, even when under the effects of the pheromones and he wanted to show Rin he was unarmed, that there was no reason to see him as a threat.

            “Okumura,” he said slowly, trying to keep his voice clear and calm and non-threatening, trying to pull Rin back by using his name, “Do you understand me?”

            Rin blinked, his eyes seeming to come in to focus for a moment. He took a step forward and then paused. “…Smells good,” he drawled, his speech slurred.

            “What?”

            Ryuuji didn’t have time to react as Rin suddenly stepped in close, too close, pressing his nose to Ryuuji’s throat and breathing deeply, smelling him—or perhaps it was the pheromones he was smelling, but it didn’t matter.

            Still, that’s all he was doing, just smelling him, and Ryuuji stood there, his face flushed and his heart pounding as Rin continued to nuzzle at his neck. It felt… Good, and Rin’s proximity caused an unfamiliar heat to rise in Ryuuji’s chest.

            Rin made little sniffling noises as he nosed at Ryuuji’s neck, down under the edge of his ear, nuzzling his hair line, and Ryuuji held his breath, struggling to ignore the ticklish little shocks of frisson that kept jumping down his spine with every little touch of skin or breath. Ryuuji bit his lip, reminding himself that Rin wasn’t in his right mind.

            Slowly, Ryuuji placed his hands against Rin’s chest, intending to put a little space between them, but the second he touched him Rin growled, a threatening rumble from the core of his chest, and he snapped his arms up, grabbing Ryuuji’s wrists, his grip like smooth iron; unbreakable and firm, but not too tight.

            Ryuuji froze again, not wanting to anger him, but when Rin began to use his strength to push him towards the ground, Ryuuji began to struggle. He definitely did not want to get in to such an indefensible position.

            Rin growled again, the sound deep and feral as they wrestled, and Ryuuji was seriously considering just hauling back and clocking him and making a run for it when Rin put his teeth at Ryuuji’s throat.

            Not a bite; a warning.

            Ryuuji stilled instantly, a bead of nervous sweat running down the side of his face. He tried to remain as still as possible, his heart pounding in his chest as Rin pressed him to the ground and climbed on top of him, his teeth still at Ryuuji’s throat. Ryuuji swallowed the lump that sat in his throat like a stone, his Adam’s apple bobbing and grazing fang.

            And then Rin licked him, his tongue hot and wet against Ryuuji’s throat and Ryuuji had to stifle a groan. This was wrong, this was so wrong. Rin wasn’t lucid. He wasn’t doing this by choice, but as Rin shifted his hips, humping the air between them, Ryuuji became blatantly aware of what exactly it was Rin was trying to do. The pheromones didn’t make demons attack their target. It made them want to mate with it.

            That explained it. There were animal species that went in to such violent mating frenzies they tore themselves, their rivals, and sometimes even their intended mate apart. Rin did not currently have any rivals to contend with, but that was hardly a comforting thought.

            Ryuuji put his hands on Rin’s shoulders and tried once more to push him away, but he didn’t budge. Instead Rin turned to look up at him, teeth bared, but there was something desperate in his eyes and Ryuuji wondered if somewhere deep down Rin was aware of what he was doing. Damn it. He wasn’t going to be able to stop him, so… so… He might as well just try to get it over with as quickly as possible.

            Ryuuji grit his teeth and closed his eyes, running his hand down between them. Rin keened in his ear when he touched him, feeling the hard bulge trapped in his pants, and Rin pressed against his hand, rutting against him like an animal in heat.

            Ryuuji tried not to look, to just lie there and let it happen, but he couldn’t ignore the noises Rin was making as the half demon pressed his face back against his throat, little gasps and moans of pleasure escaping as he pressed himself in to Ryuuji’s hand. It was disturbingly hot, the keening neediness that laced Rin’s voice, and Ryuuji swallowed the lump in his throat and tried to think unsexy thoughts as he felt himself start to grow hard in response.

            He could feel it clearly, the shape and hardness of Rin’s cock through his pants, could feel wetness pooling against his palm as Rin moved with desperate grunts and quick little jerks of his hips.

            It wasn’t like Ryuuji was jerking him off, just giving him something firm to press against, to wrap around him, and it seemed to be enough as Rin arched his back and stopped his desperate movements, shivering for a moment before going lax and panting against Ryuuji’s neck.

            Ryuuji withdrew his hand and let out a breath he hadn’t realized he’d been holding. So far this hadn’t been so bad. It was definitely not an experience he wanted to dwell on and he was sure Rin would feel the same. In fact, if Rin woke up and remembered nothing of this it would be all for the better. Of course… Rin would wake up with a sticky mess in his pants, but Ryuuji would play dumb if need be and Rin could assume he’d just passed out and had an awkward wet dream, as confusing as that would be happening in the middle of an assignment, but it had to be less embarrassing than this.

            Rin stirred and Ryuuji raised his hands to Rin’s shoulders, intent on pushing him off of him, but Rin licked him. Again! And he didn’t stop there. Rin rained little licks, nips, and grazes of teeth down on Ryuuji’s face and the older boy screwed his eyes and mouth shut as he tried to twist away.

            “Damn it! O-Okumura, stop!”

            But he didn’t stop; didn’t respond. Instead he ran his hands over Ryuuji’s face and through his hair, messing it up, as if pawing at him even as he continued to lick him. He also began grinding against him and Ryuuji had the sudden startling awareness that Rin was still hard and this whole ordeal was far from over. His attempt to get it over with as quick as possible had been futile, and had perhaps even given Rin the wrong idea, if he could even said to be aware of what was going on at all.

            Ryuuji’s heart was pounding, his dick already half hard just from listening to Rin get off, and now with the way the other boy was moving against him, licking him all over, his own breath was growing quick as he felt his arousal rise against his will.

            Rin pressed against him, directly this time, not against his hand, but between his legs and Ryuuji involuntarily lifted his hips to match the thrust, letting out a gasp. Hard, solid contact existed between them as they started to move together, but it apparently wasn’t enough for the half demon who let out a guttural growl. No longer content to rut against a hand or dry hump him, Rin ceased his rain of licks to reach down and tug at Ryuuji’s pants. Apparently too far gone to work his belt, he let out a growl of frustration and started to physically jerk Ryuuji’s body around in an effort to pull his pants off, dragging him through the grass until Ryuuji reached down and undid the belt for him, worried he might end up losing them if Rin got frustrated enough to simply tear them off.

            With the belt undone the pants slid free and Rin tugged them off. Ryuuji flushed, but didn’t have time to feel embarrassed as he clambered up and tried to run, trying to put some distance between them while Rin was preoccupied with his pants, but a second later Rin’s hands were around his ankles and Ryuuji fell, tasting dirt and grass. A moment later Rin was above him once more and he placed his teeth at Ryuuji’s throat and gently, if you could call it that, pinned him to the ground. He chuffed, a quick puff of air washing over Ryuuji’s neck before he released him, like a warning to stay put.

            And then Ryuuji could feel him, even though Rin was still fully dressed, he could feel the half demon grinding against his ass before Rin moved lower, trailing bites and nips down his back, this time hard enough to leave marks even through his shirt, as if Rin was getting tired of Ryuuji’s resistance.

_Shit, shit, shit._

            Ryuuji’s mind reeled as he lay in the grass with Rin behind him. His boxers were pulled down by a clumsy, clawed hand and left to pool around his knees. His only saving grace at this point was the fact that Rin probably wouldn’t be able to manage his own belt, and he wasn’t going to help him with _that_. Rin could shred his own pants for all he cared if it gave him time to get away. Not that he’d probably be able to get away, unless he got really lucky. He couldn’t outrun him in a dead sprint.

            Ryuuji tried to keep his breathing even as Rin gripped his hips, still trailing little stinging bites down his back, scraping his teeth across skin made extra sensitive by the cold and the adrenaline coursing through his veins. He’d never know if one of the bites was going to turn vicious until it was too late, but so far they were just hot and wet; each bite sending a shiver down his spine which he tried to ignore as his traitorous erection pressed in to the ground.

            Ryuuji struggled up to peer over his shoulder. Very soon would be his last chance to run and he didn’t want to miss it. Rin’s eyes were still hazy with lust, but they held a predatory gleam and he moved with intent, scraping his teeth down the curve of Ryuuji’s ass before suddenly licking him.

            Ryuuji tensed, his back arching at the unexpected sensation as Rin buried his face between his cheeks. He barely had the chance to realize what Rin was doing before a strangled moan escaped his throat. His arms shook and he had to resist the urge to press back against the other boy’s tongue.

            Rin was licking his ass!

            It was weird and gross and not at all what he had expected, but it felt– _Jesus_ , it felt good. Weird, but good.

            Clawed hands dug in to his hips as Rin held him still, his hot, wet tongue squirming against him. Ryuuji reached up to bite his fist in an effort to silence himself, another moan threatening to wrench itself free, escaping only as a strangled gasp as he lifted his hips, spreading his legs slightly to give Rin better access.

            Fuck. What the hell was wrong with him?

            Ryuuji buried his head in his arms as his face burned, ashamed at what he was feeling, but no longer bothering to resist as Rin continued to lick him, his hot tongue working in long solid strokes against his hole. The sounds Rin was making were sinful in and of themselves as he slurped, heavy breath panting out to wash over saliva slicked skin and all Ryuuji could do was tremble and gasp, his neglected cock weeping.

            He lifted trembling hips and Rin pressed forward eagerly. Ryuuji could still feel Rin’s teeth pressed against sensitive skin, the other boy’s mouth open wide as his tongue stabbed in to him, and he snaked a hand down between his legs as he started to jerk himself off. He _really_ hoped Rin wouldn’t remember any of this.

            Desperate pants, slurps, and the sound of rustling grass filled the small clearing as Rin continued to lick him mercilessly, his slick tongue working Ryuuji towards a fast approaching orgasm as he stroked himself. It wasn’t long before Ryuuji jerked against Rin’s face, his toes curling, and cum splattering out to stain the grass beneath him before he gave out a ragged gasp and collapsed.

            Rin’s tongue slowed and finally moved away. His hands left Ryuuji’s hips, undoubtedly leaving behind bruises, and Ryuuji could hear Rin struggling with his belt, but his legs felt like jelly and his mind far away as he struggled to come down from the high of orgasm.

            The chance to run passed and Rin was on top of him again, though still with pants on. He whined, nosing against Ryuuji’s cheek before grabbing his wrist and dragging his hand down to Rin’s pants.

            Ryuuji groaned, a sound of deep, intense suffering.

Rin was coherent enough to understand that Ryuuji could help him and was asking him for assistance. Damn it. He could feel the bulge of Rin’s erection, tenting out his pants and pressed against his slack hand as Rin held it there. The questions were: what would Rin do if he didn’t help him? What would he do if he _did_?

            “No…” Ryuuji said, though without much conviction.

            Rin’s whining increased, though it was more like desperate open mouthed panting as he pressed his teeth to the juncture of Ryuuji’s neck. Ryuuji shivered and turned his hand to palm the bulge at the front of Rin’s pants—still wet from before—and the other boy shifted in to the pressure.

_Damn it._ He could… He could just jerk him off again, right?

            Ryuuji cursed under his breath as he struggled to roll over and Rin growled, a warning that turned in to a whine as Ryuuji squeezed him through his pants, silencing him. He got both his hands up and started to work Rin’s belt, the half demon shimmying out of his pants and underwear the second the belt came loose.

            He was on Ryuuji again in an instant, grabbing his face and licking him once more, the little kisses turning to affectionate nips as Ryuuji struggled to push him off. Damn it! After where Rin’s tongue had just been?!

            Ryuuji didn’t have the strength to fight him off. He screwed his eyes and mouth shut, but couldn’t turn away as Rin held him in place, licking him like a dog, his tongue sliding across his face in broad even strokes.

            “D-Damnit, Rin! Stop-!”

            Ryuuji was cut off abruptly, his eyes snapping open as he found Rin’s tongue invading his mouth, the other boy kissing him clumsily, their teeth clacking together. Rin released Ryuuji’s face to reach down, grabbing his legs and trying to get him in to position only for Ryuuji to immediately turn his head away from the kiss. He sucked in a lungful of air, catching his breath, and Rin latched on to his neck instead, completely undeterred.

            He lifted Ryuuji’s knees, pulling his hips up and the other boy tensed, but he only had a second to mentally prepare himself as he felt Rin’s cock poised at his entrance. He was still slick with saliva, but the tongue laving he’d gotten hadn’t been nearly enough to prepare him and Ryuuji sucked in a sharp breath as Rin pressed in to him. He scrabbled, trying to shove Rin off of him, but it was like pushing against a mountain as Rin held on to him with hands and teeth.

            Rin was panting, straining, pressing in on him slowly, but steadily. His tongue moved lazily against the juncture of Ryuuji’s shoulder as he held him in an open mouthed bite, releasing a soft keening whine as he seated himself inside the boy beneath him.

            Ryuuji bit his lip as he tried to keep silent, tried to keep his breathing easy and steady, to remain calm as Rin started to move. It hurt. It definitely hurt. It hurt so much he couldn’t even think, all he could do was cling to Rin as the half demon started to move, all breathless grunts and uncoordinated thrusting.

But then Rin was whining again, nosing at his mouth, and Ryuuji realized he was biting himself so hard he was bleeding. Blood dribbled down his chin and Rin swiped it up, his             tongue sliding gently over Ryuuji’s mouth before he returned to his shoulder and bit him again, this time hard—much harder than before—and Ryuuji winced, panic rising in his chest as he realized that maybe the blood had set Rin off and this might be it. He was going to die with Rin’s dick in his ass as the other boy fucked him and ate him at the same time.

            But then Rin pulled away, soothing the fresh wound with a whine and his tongue, the same as he’d done for the bloody lip, before reaching up to cradle Ryuuji’s head and pressing his own neck against Ryuuji’s mouth.

            Ryuuji didn’t move, his heart still pounding. He didn’t know what Rin wanted him to do. He was still surprised he wasn’t dead yet, even as Rin started to nuzzle the side of his head, encouraging him.

            When he didn’t move, Rin pressed his teeth to Ryuuji’s neck again, over the wound he’d just given him, before licking him again, just a quick swipe of his tongue, then lay his own neck across Ryuuji’s face once more. The half demon was shaking, still buried to the hilt inside of him, but otherwise holding still, as if just waiting for Ryuuji to act.

            Did… Did Rin want him to bite him?

            Tentatively, Ryuuji opened his mouth, placing it against Rin’s shoulder. Rin leaned in encouragingly. Even as he pressed his teeth against Rin’s skin the other boy didn’t pull away, so Ryuuji bit down, but his teeth were nowhere near as sharp as Rin’s and he didn’t draw blood. Rin grunted, but leaned in to him, urging him on so Ryuuji shut his eyes and bit down until the coppery tang of blood filled his mouth. He pulled away, spluttering, disgusted the moment it hit his tongue, but Rin forced his head back and Ryuuji had no choice but to lick the wound the same way Rin had done to him. It only took a moment for the effects to kick in.

            His vision began to swim, dulling at the edges, and everything started to feel … a little bit fluffy and warm. Very warm. Almost hot even. Ryuuji’s head lolled and Rin released him, apparently satisfied, before rolling his hips, thrusting shallowly in to the boy beneath him.

            Oh… Right. He’d almost forgotten about this… They were fucking. Or more accurately Rin was fucking him. He was being fucked by his half demon friend and partner. Ryuuji cursed himself for not anticipating that the pheromones could have an effect on him through Rin’s blood, perhaps even his saliva, if that’s what this was? Maybe this was normal for demons. It’s not like he’d studied their mating habits before. Exorcist studies tended to focus solely on extermination.

            It still hurt, but the pain was quickly fading, giving way to intense heat and something more as Rin grunted and moved above him. Rin’s thrusts were erratic and uncoordinated, shallow little thrusts likely concerned only with his own release, but at least it no longer hurt, and somewhere in the back of his fading mind Ryuuji realized he was hard again, painfully so—Perhaps another side effect of whatever was happening to him.

            A lazy moan slipped past Ryuuji’s lips and he clung to Rin, like clinging to his last grasp on reality as the world spun. Again, it was the sounds Rin was making that were doing it, more than anything else, and Ryuuji found himself meeting Rin’s thrusts, wanting, needing something more than what he was getting, and Rin growled as he grabbed his hips and latched back on to Ryuuji’s neck, using the added leverage to start pounding in to him.

            Rin’s animalistic grunts and growls, and the sound of slapping skin filled the air, drowning out Ryuuji’s desperate gasps. He clawed at Rin’s back, trying to stop him from pulling out and failing every time, but rejoicing at the return, only to mourn the loss seconds later and repeat the process over, again and again, until finally, with one last desperate growl Rin bit down on his shoulder again, drawing fresh blood even as he slammed his hips against Ryuuji’s, driving his cock home and spilling himself deep inside him.

 

* * *

 

 

            Ryuuji did not remember coming a second time. When he came to, Rin was collapsed against his chest, unconscious or asleep, and it was with a great deal of discomfort and disgust that he felt Rin slip out of him as he shifted, rolling the oblivious half demon off of him.

            He reached up to rub his aching neck, his hand coming back with faint streaks of blood, but it was crusty and dry, clearly clotting properly, well on its way to healing. Hopefully. He wondered idly if he’d need to be treated for temptaint as he stood on shaky legs to retrieve his pants, but that would have to wait for a doctor. He dressed quickly, then hesitated as he stood over Rin’s unconscious body and sighed.

            A confusing knot of emotions bubbled inside him. Envy, that Rin could appear to be sleeping so soundly after what had just happened—after what he’d just done. Guilt and remorse, for enjoying it, for giving in, for letting it happen. He could have fought harder, he could have–

            He laughed bitterly. Rin could have snapped him in half like a twig if he’d wanted to; ripped out his throat with his teeth. Maybe—just maybe—if he’d been more alert, or if Rin hadn’t distracted him, or if he’d acted quicker, or if he’d considered that Rin might be effected by the hormones, or even if the threat level of the mission had been properly assessed and the order not assigned two exwires to go deal with a fucking Gate Keeper on their own…

            Ryuuji took a shaky breath.

            If, if, if…

            In spite of it all he couldn’t bring himself to hate Rin, or even be mad at him. Well, maybe a little bit. He glared at the half demon as he slept, oblivious to Ryuuji’s inner turmoil and then swiftly kicked him in the back.

            “Augh, what the fuck?!” Rin cried out, cursing in pain as he rolled over to glare up at him, only to do a double take as he realized he was half undressed and outdoors. “W-what the– Why-? W-where…?” Rin floundered as he tried to cover himself, completely at a loss towards his current situation and Ryuuji found himself relaxing slightly, if not taking a little comfort in Rin’s distress.

            He was speaking, even if somewhat incoherently—a step in the right direction. Ryuuji threw him his pants.

            Rin caught the offending article, his cheeks coloring as he stood to dress even as Ryuuji turned away. Silence passed between them, unnatural for Rin, and Ryuuji could feel him approach.

            “Suguro?” Rin’s voice was quiet, tentative, and for a split second Ryuuji was worried he might apologize.

            “What happened to your neck?”

            Oh. He reached up instinctively, touching the tender flesh once more.

            Rin didn’t remember.

            “Got bit,” he said with a shrug that sent the bite aching, but the only outward sign was his usual continual scowl.

            “Shit, man… I’m sorry,” Rin said, and Ryuuji paled, but Rin continued, “I should have… I should have protected you? I don’t… really remember... My head’s still fuzzy…” He rubbed his eyes and shook his head, as if trying to remove the veil that obscured his mind.

            It was weird, seeing Rin so out of sorts, so clearly unsure of himself.

            Ryuuji shrugged. “All that matters is you killed it. Mission was a success.”

            “Really?” Rin quirked a brow at him, skeptical, “You ain’t gonna’ yell at me for spacing out?”

            “I already kicked you. I’m good.” He turned away from Rin, unable to meet his eyes, unable to keep up the charade of normalcy for much longer. Oh, he’d do it forever, if need be. He just needed time to sort through what he was feeling before locking it securely away.

            “Let’s get the hell outta here. I’m starvin’.” It was true. It was still an excuse, but it was one Rin could agree with and Ryuuji released a quiet little sigh of relief as Rin hurried to grab Kurikara and then fell in step beside him without further protest.

            But he couldn’t help notice out of the corner of his eyes as Rin reached up to rub his own neck, grimacing lightly even if he couldn’t see the bite wound that still appeared oddly fresh; a set of humanoid teeth marks—Ryuuji’s teeth. And he found himself idly hoping that Rin’s demonic healing would set in, hiding the evidence before he noticed it.


	2. Chapter 2

**Summary for the Chapter:**

> How do you face the person who hurt you when they don't even know they did it?

**Notes for the Chapter:**

> Here it is, the much anticipated continuation that probably no one wanted to be angst.

            Ryuuji tugged at his shirt collar. The bandages on his neck were barely visible. The bite appeared to be healing properly, scabbing over without infection, but he’d gotten checked out after the mission and had been treated for temptaint, just to be on the safe side. When the doctors asked he told them it was a goblin bite, and aside from that he’d only gotten a few minor cuts and bruises, including a rather nasty one forming on his lower back, though he wasn’t quite sure how he’d gotten it. None of it was the result of combat, but no one else would ever guess that.

            He felt fine, mostly, physically… Nothing to miss school over—he’d certainly had worse, and yet… He sat on the edge of his bed, clenching his eyes shut as he tried not to think about it. Going to school, getting on with his life, and pretending as if nothing had happened would be the best way to get past this, but…

            Rin’s face flashed in his mind—those vacant eyes, the teeth, right in front of his face.

            Ryuuji rubbed his eyes, trying to erase the image and took a deep breath to steady himself before lying back down, his back towards the rest of the room. A day or two to think and process the events and just rest wouldn’t hurt either.

 

* * *

 

 

            Rin scratched idly at his neck, not so much paying attention to his brother’s voice as staring at Ryuuji’s empty seat. He had to assume Ryuuji was okay. He’d walked away from the mission on his own and surely someone would have said something otherwise, but it was unusual for the other boy to miss school. He couldn’t shake off the odd nagging feeling that had settled in the pit of his stomach like bad food.

            “Migraines” is what Shima had said when he’d asked about it, but one day had turned in to three and the feeling of dread had only grown. Migraines weren’t _that_ bad, were they? Rin didn’t really know, but either way he found himself in front of Ryuuji’s dorm room after class one evening, knocking before he’d even taken the time to think about what he’d say.

            Soft footsteps sounded from behind the door before Ryuuji opened it. He flinched, his face going white before he could smooth his expression in to his usual scowl.

            “O-Okumura? What are you doing here?” Ryuuji did not invite him in, didn’t even open the door all the way, shielding the entrance with his body.

            Rin had raised his hand in greeting, but the cold reception brought him up short and he wilted at Ryuuji’s tone. The nagging feeling that something was wrong grew.

            “I… just wanted to check on you,” he said, though he was beginning to feel like an idiot. Ryuuji looked fine, and Shima and Konekomaru would have said something if that weren’t the case, but there he was, unable to shake the sense that something was wrong anyways. Not that he could say that without looking like a paranoid weirdo. Damn, he should have brought Ryuuji’s homework, or a get-well gift or something to justify his presence.

            “It’s just you’ve missed a couple days of school is all.”

            “I’m fine. It’s just migraines,” Ryuuji said curtly, as if that should be the end of it, but when Rin didn’t look like he was going to move he added, “Was there anything else?”

            “…Can I come in?”

            Rin didn’t miss the way Ryuuji grit his teeth, the muscles along his jawline tensing, or the fact that he did not immediately answer.

            “Okumura-kun!”

            They turned to see Shima and Konekomaru coming down the hallway.

            “You come to check on Bon? Isn’t that sweet,” Shima cooed, “Come in, come in. No point standing around in the hallway.”

            Ryuuji hesitantly stepped back from the door to let Shima and Konekomaru in, but his eyes drifted back to Rin as he lingered in the hallway, as if waiting to see what he’d do. Their eyes met and Rin’s gaze dropped towards the floor, his hair hiding his face.

            “Nah, it’s cool,” Rin said somewhat stiffly, “I just… came to check on ya’… Yukio’ll probably want me back soon else he’ll nag me about homework or something.”

            Rin spun on his heels, his arms tight at his sides as he walked, his head down, but he stopped a few feet from the door.

            “Feel better, kay?” he called over his shoulder, before sprinting off down the hallway.

            Ryuuji watched him go and then sighed, closing the door to his room with a shaky breath he hadn’t realized he’d been holding.

            That was just not fair. After what had happened, why did he feel guilty?

            He rubbed his temples, taking another deep breath and trying to steady himself before he faced his friends. Even after three days he had not been ready for that—ready to face Rin. At least not like that. Alone. Cornered. With Shima and Konekomaru in the room, he might have been able to, but…

            He’d have to get used to it. He was doing the homework Konekomaru brought him with relative ease, but there was only so much school he could miss before his grades would start to slip.

            And he couldn’t avoid Rin forever. He didn’t really want to try either. They had been friends. It could—had—to go back to the way it was before.

            “You okay, Bon?” Konekomaru asked, and Ryuuji realized he’d been staring at the door, his body still on high alert having been faced with a threat. He still wanted to run, to hide, even though the threat was gone… Even though, he had to consciously remind himself, there was no threat.

            He resisted the urge to bury his face in his hands and scream, instead turning to face his friends.

            “Y-yeah,” he said somewhat shakily, “Just… migraines.”


	3. Chapter 3

**Summary for the Chapter:**

> Ryuuji attempts to go back to school, but still not entirely understanding his situation things spiral out of control and go real real bad, real quick, for both of them.

            Ryuuji was ready to go back to school, or at least that’s what he kept telling himself as he stared himself down in the mirror that morning. Three days was enough. It had to be. Continuing to hide would just drag things out. He wasn’t wholly without a plan though.

            He stayed in class during the lunch break and made sure he didn’t go anywhere alone, so if he did run in to Rin by chance he wouldn’t have a repeat of yesterday, finding himself alone and trapped. By the time cram school rolled around he’d steeled himself towards the inevitable.

            As usual, Rin arrived just barely on time. Ryuuji held his breath and forced himself not to look up as Rin entered the room—not to recoil or react, or give in to the impulse to run. He barely nodded in his direction when the half demon threw him a casual greeting, struggling to crush the rising sense of panic that gripped his chest like an icy hand. He could feel Rin’s eyes on him for the split second that they lingered in confusion, before Rin looked away, taking his seat, and Ryuuji breathed a quiet sigh of relief.

            He could do this. Just act natural. If he was too distant then Rin would seek him out again, but at the same time it wasn’t like he _wanted_ to cut Rin out of his life entirely anyway. He really didn’t blame him for what had happened, he just… He just needed to be in control while acclimating himself to Rin again, and hopefully that sense of fear and dread would go away, and with them the guilt.

            If Rin really didn’t remember anything then he had no idea why he was being snubbed. The look on his face last night… It was the way he’d looked after the forest training camp incident, his expression practically begging someone to reassure him that everything was alright, that his friends weren’t suddenly afraid of him… Except Rin hadn’t hurt anyone then. He didn’t know he’d hurt anyone now either…

            Damn it!

            Ryuuji whipped his notebook open as the teacher started to lecture, furiously taking notes in the hope of blocking out any other invasive thoughts. That was what he was here for anyways; to learn. To learn, while at the same time trying to get used to Rin again, but no matter how he tried to keep his nose down and his thoughts focused he couldn’t escape the weird feeling gnawing at his gut—guilt, but not quite. Something else.

            He glanced in Rin’s direction and almost flinched when he saw that Rin was looking at him, his skin burning as he dropped his eyes back to his own notebook. A more surreptitious glance told him that Rin was still watching him, his brows drawn together in obvious concern. Ryuuji grit his teeth, trying to ignore the guilt that gripped his chest and carried on taking notes, trying to focus on the teacher’s words instead.

            It should have been Rin who felt this way, and yet Ryuuji was not about to tell him why. That would just draw things out, making them even more awkward, and if he knew Rin at all the half demon would beat himself up over it far worse than Ryuuji ever would.

            It was just… Why did _he_ have to feel like this? He was the one that had been wronged! The one who’d been hurt!

            He cursed under his breath as his vision blurred, darkening at the edges as a dull ache found a home behind his eyes, pulsing in time with his erratic heart beat and growing quickly in intensity.

            A migraine. Just great. Just fucking great. This was all he needed, today of all days, as if his suffering hadn’t been compounded enough.

            He clutched at his head as he tried to keep writing, his grip on his pencil white knuckled and desperate as he dug it in to the page hard enough to tear paper. The teacher’s shrill voice was like daggers stabbing his brain, and he could still feel him—Rin’s eyes on his skin, burning him like hellfire.

            He just…

            He needed things to be like before… Before it happened. Pretend like it never happened. Like things were normal and he wasn’t afraid- Afraid of his friend- A demon- his friend- his-

            “R-Rin?”

            The trembling concern in Shiemi’s voice snapped him out of the downward spiral and he looked up, taking a deep breath before the panic could take hold.

            He’d been about to start hyperventilating, even now struggling to breathe normally, but when he looked over at Rin he realized the other boy wasn’t fairing any better. Rin was clutching his chest, sheet-white and covered in sweat, gritting his teeth in obvious pain. Shiemi’s hand rested gently on his shoulder, concern etched deep on her delicate face.

            Despite his own distress Rin turned to face him, reaching out to him. Ryuuji flinched backwards, away from Rin’s outstretched hand yet regretting the unconscious reaction instantly as another wave of guilt washed over him. Rin pulled his hand back, his lip trembling as he struggled up out of his seat only to collapse to the floor.

            What the fuck was happening? This wasn’t what Ryuuji wanted at all. He just wanted things to be normal again, but he couldn’t help the way he felt! It wasn’t his fault! It wasn’t- He didn’t-

            Ryuuji’s vision swam. The world spun and the floor jumped up to meet his face before everything went dark.


	4. Chapter 4

**Summary for the Chapter:**

> Rin and Ryuuji finally find out what's wrong with them, and when the verdict is coming from Mephisto, you know it can't be good.

**Notes for the Chapter:**

> Apologies if there are mistakes or anything like that. This story is already late, and I'm going through some shit right now, but I don't want to put off posting this much longer.  
> Thanks as always for reading and reviewing!

            Ryuuji knelt on the ground as rain poured down around him, rot and refuse clinging to his tattered cloak as he maintained the barrier restraining the Impure King. The situation seemed impossible—he teetered where he knelt, the exhaustion nearly overwhelming his senses as pustules of disease sprouted up around him—but he wasn’t scared.

            Rin turned to him, waving Kurikara in the air, smiling even as torrential rain plastered his hair to his face, trying not to let the situation get to him; trying not to let it get to either of them in the face of Ryuuji’s apparent certainty that he was about to die; that Rin should run and save himself, should try to save the others.

            He could see it then—the false confidence, the goofy exterior that masked the darkness within—and yet Ryuuji remembered the words before he spoke them, as if watching the events from outside his body.

            “We’re friends, after all. I’ll trust you.”

            And he did. He meant those words. Even if he didn’t think Rin could save him, he’d already resigned himself to a last ditch effort at a noble death, sacrificing himself to buy the others more time. The company would be nice.

            And with those words Rin drew his sword just the way Ryuuji remembered. His flames burst to life around him, turning the rain to steam before it could hit him. His fangs elongated, like serrated daggers in his mouth, and his eyes were wild and unfocused as he charged.

            Ryuuji’s heart stopped; his eyes wide and locked on those inhuman teeth as Rin barreled towards him.

            Contrary to Ryuuji’s memories Rin did not pull up at the last second to slice through the pustules of disease that was slowly enveloping Ryuuji’s body, he just kept coming forward until those teeth, those snarling fangs, were all Ryuuji could see; until he was pinning him to the ground, that hellish day in Kyoto and the rot and disease of the Impure King replaced by the forest, the rain replaced by the quiet hush of wind passing through leaves and grass as the sun danced over their bodies, warming their skin.

            Ryuuji woke with his heart hammering in his chest and his body covered in sweat as his head swam with the last vestiges of his dream. The light stung his eyes and it took him a moment to focus on the cold, unfamiliar white tiles of the ceiling. He took a deep breath to calm himself and looked around.

            He was lying on a cot, surrounded by a privacy curtain—in the infirmary no doubt. The last thing he remembered was being in class, and he had no idea how he’d gotten there, which meant he’d probably lost consciousness. He groaned as he rubbed his eyes, shielding them against the blinding light of the overhead fluorescents and hoping his migraine would not return.

            The infirmary door clicked open and Ryuuji froze as two people entered the room. He wasn’t sure why. It wasn’t like he wasn’t supposed to be there, but he remained quiet as they began to speak.

            “I don’t know what’s wrong with them. Both their vitals are completely normal.”

            “I think I can answer those questions.”

            “If you know something…”  

            “It’s a delicate personal matter, but I assure you they’re in no immediate danger. I’ll take things from here.”

            Ryuuji didn’t recognize the first voice, but the second voice instantly had him on edge. It was Mephisto, and he found himself leaning forward in the cot, straining to hear the rest of the hushed conversation as the first person whispered furiously and they began to argue.

            He couldn’t make anything out. Instead the muted conversation on the other side of the room stopped and one of the participants left the room, their footsteps echoing down the hall before the door was closed, leaving the room uncomfortably still and silent, but Ryuuji knew Mephisto was still there.

            He wasn’t at all happy to be left in the Headmaster’s care. No immediate danger? What did that even mean? Was there _distant_ danger? What did Mephisto know that a doctor wouldn’t? Ryuuji had too many questions, and none of the answers could be good when high level demons were involved.

            Footsteps sounded much too close to his bed, and Ryuuji could see the headmaster’s silhouette through the curtain. The shrill ring of metal sliding across metal and clinking together sounded as Mephisto drew back the cheap plastic privacy curtain on the adjacent bed.

            “Rise and shine, little brother.”

            “…What happened?” Rin’s voice came from the next bed over, groggy and disoriented.

            Mephisto drew back the curtain around Ryuuji’s bed too and smiled down at him— the same unsettling smile he always wore.

            “I think you’ll want to hear this too,” he said.

            Ryuuji sat up, his head swimming briefly with the sudden motion, but the vertigo passed. He glanced at Rin and found him staring with open concern, but he looked away when their eyes met and once again that tight knot of guilt stabbed at him. This time he shoved it down, ignoring it. He was not the one who should be feeling guilty, and besides, they had more pressing matters to worry about.

            “What’s going on?” he asked, getting straight to the point.

            “Well, I have good news and bad news,” Mephisto said, dangling the question in front of them.

            “What’s the good news?” Rin asked, taking the bait.

            “I know exactly what’s wrong with you,” he said with a smirk, as if _that_ could be good news. Undoubtedly, the bad news was the verdict.

            “And?” Ryuuji pressed.

            “Why, it has to do with those bite marks on your necks,” he said with a dramatic flourish of his hands, as if that explained everything.

            Ryuuji flushed, slapping a hand over the mark on his neck as if he could hide it when a single look at Mephisto told him everything he’d been dreading. Mephisto knew exactly what the bites were—probably how he’d gotten it, and from who. His face burned and he looked away, afraid of giving away something more.

            “Bite marks?”

            They both looked over to see Rin tugging on his shirt collar, trying to look at his own neck. It took him longer than it should have to give up on that and go look in a mirror, but there it was—a fresh scar roughly in the shape of human teeth. “Where…?”

            “Did you not realize you had that?” Ryuuji asked incredulously.

            He’d been so dead set on trying to ignore the other boy’s presence that he hadn’t realized Rin’s bite hadn’t healed perfectly like he’d expected it to. When Rin didn’t say anything he assumed it had, but for Rin to not notice…

            “I don’t know,” Rin said, his cheeks coloring as he crossed his arms over his chest with a pout, “I knew it was there, I just thought it’d go away.”

            Mephisto tutted, shaking his head.

            “Dear brother, the next time you acquire a wound that does not heal properly within a few hours, it might behoove you to assume that it’s more than it seems, and seek assistance.”

            Rin rolled his eyes, ignoring the admonition. “Anyways, what do they mean?”

            “The bites? Well, they’re like rings,” Mephisto said, shaping his fingers in to a circle.

            “Rings?” Rin and Ryuuji asked almost in unison.

            “Yes, you know. The ones humans exchange?” Mephisto asked, searching for the term, “Wedding rings. Or perhaps wedding vows would be more apt, seeing as the bites are an implicit vow unto themselves.”

            “Wedding… vows?”

            Ryuuji paled and looked at Rin, confusion giving way to dread.

            “Yes,” Mephisto said as he started to pace the small room, “It’s quite rare, actually, that demons would choose to take a permanent mate, much less a human of all things—I didn’t even know it was possible—but the shared bites serve to mark mutual ownership over one another. It’s a simple ritual. You bite one another, drink the other’s blood, taking a part of them inside yourself, and the pact is sealed.” He stopped in front of them again and clapped his hands dramatically before clasping them together and twining his fingers, signifying the bond.

            Mephisto had said all this with the air of a teacher giving a lecture and trying to drum up feigned excitement for a body of disinterested students, but Ryuuji felt as if he’d just been given a terminal diagnosis. The room felt small and cold, as if it was closing in on him. He could see his life narrowing down to a very uncomfortable reality.

            “H-how… How do we undo it?” Ryuuji asked, trying to ignore his racing heart and think the problem through logically, “There must be a way to annul the bond?”

            “I’m afraid, Suguro-kun, as far as I know, a demon’s vow is eternal.”

            “I’m NOT a demon!” Ryuuji shouted, catching himself a second too late. Shouting at the headmaster was probably not a good idea, especially not when he was a demon, but Mephisto only stared down at him with an apathetic, almost amused smile, as if Ryuuji were a small child and the outburst were only natural.

            Ryuuji clenched his fists, knotting them in the cheap infirmary blankets. It felt like someone had twisted a knife in his gut and he couldn’t pinpoint why. Damn it, it must have been the stupid bites. The vow. That was supposedly how they ended up in the infirmary in the first place.

            “And so?” Ryuuji asked, “What are the “side effects” of this vow?”

            “How astute of you,” Mephisto said, “Part of the reason it’s so rare is because demons are loathe to tie themselves to another being. You two are now tied together by an unseen link. You can sense the other’s emotions and physical well-being. If one of you should die, so shall the other.”

            Ryuuji buried his face in his hands and sighed. That’s the last thing he needed; having his physical well-being tied to a reckless fight-happy idiot. It was one thing when Rin could bounce back from seemingly the worst injury, as if he’d gotten nothing more than a papercut, but how would it affect him?

            “That’s why I’ve been feeling so strange the past few days, isn’t it? Why we ended up here?”

            “Quite so. Like a feedback loop your negative emotions have been feeding in to each other, amplifying each other. I know the circumstances are difficult, but my advice would be to try to get along and get used to the situation.”

            Ryuuji gave Rin a sidelong glance, but the other boy was quiet, staring sadly in to the distance, looking for all the world like a kicked puppy. He felt like it too, if Mephisto was to be believed. Ryuuji was conscious of his own frustration and anger, but beneath that he felt loss and longing as well. Did those feelings belong to Rin? He was probably thinking of Shiemi or something; mourning his crush on the girl before he even had a chance to act on it.

            “Look,” Ryuuji forced himself to say, gritting his teeth, “This… It’s not _that_ bad, right? We just have to watch each other’s backs. It doesn’t have to change anything. We just get on with our lives and live them normally.” It was about the last thing he wanted to be doing right now, with what had happened, but apparently keeping his distance from Rin wasn’t a fucking option either.

            “Allow me to clarify one last thing,” Mephisto said, his voice deadly serious, “The bond is, for all intents and purposes, a marriage. I didn’t use that metaphor to be poetic. Demons don’t do it out of convenience; Far from it. That’s why…There is one way I know of to free one of you from the vow. Should you ever be unfaithful, the other party will be freed from all obligations, while the cheating party will die a horrible and painful death.”

            The room sat silent as Mephisto’s words sank in. Ryuuji felt as if he’d been dunked in ice water, his senses shutting down. All he could think about were those final few words.

            Rin and Ryuuji were, by demon vow, married. They could not simply choose to wash their hands of the situation and live separate lives. Even if Ryuuji remained celibate as a monk as he’d always thought he would, Rin would be forced to remain celibate as well, his physical and emotional well-being directly impacting Ryuuji.

            “I know it’s a lot to take in, so I’ll leave you two be for now,” Mephisto said.

            “Wait! What are we supposed to do now?” Ryuuji asked.

            “That is up to you, but I will say, the school makes special exceptions for married students to live together.” And with that he laughed, before snapping his fingers and disappearing in a cloud of purple smoke.

            Ryuuji sat stunned, gritting his teeth at Mephisto’s parting words. Like hell he was going to live with Rin. He probably wouldn’t have been able to stomach that much of the half demon even before everything that had happened.

            But at that thought he glanced over. Rin had been suspiciously quiet throughout Mephisto’s entire explanation and now that the headmaster was gone, Rin sat silently on the edge of his cot, his head down, his shoulders stiff.

            “…Okumura?”

            Rin flinched, hunching in on himself.

            “Oi! Were you even listening?”

            “… I bit you.”

            “What?”

            “I bit you.” Rin swiped at his face, brushing away frustrated tears that threatened to spill from his eyes, “I’m a monster. I was supposed to protect you, but I-”

            Rin cut himself off just as Ryuuji realized that he could feel it. That feeling, twisting in his stomach like a knife, was Rin’s guilt. It was his only warning as Rin stood and fled the room.

            Ryuuji cursed, throwing aside the infirmary blanket as he gave chase. Rin’s tail was just disappearing through the stairwell door as Ryuuji entered the hallway and by the time he made it to the stairwell Rin’s footsteps were already echoing down from a few floors up.

            Damn it. He didn’t have the time or patience for this, but he could feel it now for what it was, not totally indistinct from his own feelings, but somehow different. Rin’s guilt gnawed at him, weighing him down. Was this what it felt like? Did Rin feel like this often? It wasn’t even really Rin’s fault and yet Ryuuji didn’t think he’d ever felt this guilty about something in his entire life.

            When Ryuuji got to the top floor he found the door to the roof ajar. He stepped outside to find Rin with his back turned and his head down, sitting with his legs hanging over the edge.

            “Okumura?” Ryuuji cautiously approached him.

            Rin stood, but didn’t turn to face Ryuuji. He stayed on the ledge, overlooking the academy grounds.

            “Y-You should s-stay away from me,” Rin said, his words stuttered and broken, his voice tinged with evidence of tears. “I’m a m-monster. I can’t do anything right, and all I d-do is hurt the people around me.”

            He braced his knees, leaning out over the edge and Ryuuji’s heart lurched.

            “Don’t!”

            He darted forward without thinking, pulling Rin back by the waist and they tumbled to the roof together in a tangle of limbs. Rin scrambled up off of Ryuuji a bare second later, back peddling and creating distance between them before glaring down at Ryuuji as he wiped back angry tears.

            “Dude, what the fuck?”

            “Don’t do it!” Ryuuji said quickly, reaching out as if to grab Rin and pull him back again. “It wasn’t your fault!”

            “D-Don’t do what?” Rin asked, staring at Ryuuji incredulously.

            “Don’t… Jump?” Ryuuji asked, suddenly unsure of himself.

            Rin snorted, then burst out laughing, actually clutching his stomach and doubling over to lie on the roof. When the laughter finally died down he stood up, wiping fresh tears from his eyes, but this time he was smiling and that sense of guilt Ryuuji felt had died down to dull background noise—still there, but not so overwhelming.

            “Did you seriously think I was trying to kill myself?” Rin asked, and Ryuuji’s cheeks darkened at the utter disbelief in his voice. “You know a fall from this height wouldn’t kill me, right?”

            “What? Of course I didn’t know! We’re like five stories up! Any normal person would be dead!”

            “Yeah…” Rin said, chuckling self depreciatively as he glanced away from Ryuuji, staring off in to the horizon, “I’m not a normal person. I’m also not stupid enough to do something like that now that we’re… you know… Now that it would kill you too.”

            Ryuuji stared at him blankly, his mouth dropping open. It wasn’t that he’d forgotten about that ‘little’ aspect of the situation, but in the heat of the moment he hadn’t even considered it.

            “Sorry…” he said, scratching the back of his neck.

            “Nah, it’s cool… Thanks though.”

            “For what?”

            “For pulling me back.” Rin smiled softly—a look that didn’t fill his eyes with their usual warmth. “And I guess for not being afraid of me anymore?”

            Ryuuji flinched and glanced around the empty rooftop, Rin’s reminder making him suddenly, intimately aware of the fact that they were alone. Dread gripped him, followed very quickly by the return of the guilt.

            “Sorry…” Rin backed away, his head down.

            “No,” Ryuuji said softly, “I’m sorry too. You didn’t seem like you remembered, so… I thought I could just pretend it never happened and things would go back to normal, but… it didn’t. I didn’t realize you could feel it.”

            “Not your fault… I’d probably be afraid of me too,” Rin said with a dry laugh, returning to his seat on the ledge.

            “I’m not-”

            He was about to say he wasn’t afraid—an automatic denial—but that would be an awfully bold faced lie when Rin could feel it. Ryuuji sighed, scrubbing his hand through his hair as he collected his thoughts.

            “I know that you weren’t in control of your actions. I don’t blame you, but… part of me… just can’t help it.”

            Rin shrugged, kicking his feet idly as they hung over the edge. “It’s not the first time I lost control…”

            “This was different. It wasn’t your flames or anything like that, it was the pheromones.”

            Rin shrugged, as if that didn’t even matter. Maybe it didn’t. Maybe the fact that he was a half demon and at risk to these kinds of things automatically made him dangerous—dangerous to be around or to partner with, to have to rely on. There were plenty of people in the organization who chose to avoid him outright for that exact reason.

            “I hurt you.”

            “Yeah…”

            “I bit you.”

            “Yeah, but… I bit you too.”

            “Probably self-defence,” Rin said, not even questioning the fact, which was a little bit alarming in and of itself. “…Did I do anything else to you? While I was out?”

            Ryuuji sputtered, then snapped his mouth shut, his face and body burning with shame at the memory, eyes widening as he realized what Rin was asking him to say, even though he couldn’t possibly know. Please, God, let him not know.

            “Oh. My. God,” Rin stiffened then slowly turned towards him, his face stark white. “What did I do?”

            Oh fuck. Rin could feel that too, of course. Just fucking great.

            “What did I do?” Rin asked again, desperation edging in on his voice.

            Ryuuji shook his head, taking a step back. Rin scrambled up from the ledge, advancing on him and Ryuuji flinched away. Rin instantly stepped back, hands up as he kept his distance.

            “I’m sorry, I’m sorry,” he said quickly, “I just… It happened to me too. I have a right to know.”

            “It didn’t _happen_ to you!” Ryuuji spat. A rage like he hadn’t felt in years bubbled up inside him, threatening to boil over. It was most certainly his own emotion, but its sudden arrival shocked both of them and Rin recoiled even as Ryuuji clenched and unclenched his fists, trying to battle the feeling down.

            Rin had been an unwilling participant in his own actions, but what he did, he did _to_ Ryuuji. It didn’t even compare and Ryuuji seethed at the implication that Rin had been affected the same way he had.

            And the worst part was… It would kill him if he found out.

            He didn’t want this. For both their sakes, Rin couldn't know.

            “Just… Listen,” he finally said, his voice flat and hard like stone as he reigned in his feelings, shutting them down and very carefully choosing his words. “What happened, happened to _me_. I don’t blame you—you weren’t in control,” he repeated, as much to convince himself as to convince Rin, “But I got the rawer end of that deal by far, and… you shouldn’t ask questions you don’t want the answers to.”

            His words hung in the air with a sense of finality. Rin didn’t protest, simply hanging his head. Ryuuji could still feel the guilt, but he didn’t know what he could do about it. Rin deserved to feel guilty, but what he felt now wouldn’t even compare if he knew what he’d really done. He’d just have to get over his curiosity, and in the meantime Ryuuji would have to learn to ignore the guilt.

            “So… Rin finally said, gesturing to the bites, “What do we do about these?”

            Ryuuji shrugged. “If Mephisto’s to be believed, there’s nothing we _can_ do, but I’m not going to sit back and take his word for it.”

            “Oh, I meant… um- Never mind…” Rin trailed off, and Ryuuji didn’t even need the link to feel his hesitation and embarrassment.

            “What is it?”

            “I just meant more like… what do we tell everyone?”

            “I ain’t telling nobody nothing!” Ryuuji snapped, “Don’t tell me you were just going to accept this?”

            “Of course not, but… I don’t know what else to do, so… I guess I’ll just wait for you to figure it out. You’re the genius after all.”

            “I just study properly,” Ryuuji said, flushing lightly at the unexpected compliment. He couldn’t really argue the point though. If Rin couldn’t kill the problem, he was just about useless. “I guess I’ll look in to it. Let you know what I find.” He stood and dusted off his pants before heading for the stairwell.

            He stopped on the threshold, his fingers drumming idly against the door frame. He could feel Rin behind him, languishing in his own personal emotional hell. He didn’t even have to turn to look. “…Okumura?”

            “…Yeah?” Rin asked hesitantly.

            “See ya’ tomorrow.”

            And with those simple words the guilt softened slightly, leaving both of them feeling a little bit lighter—not quite absolving Rin of the guilt, but it was a sign that Ryuuji would accept him back in to his life, albeit hesitantly.

            Even if he had to force himself to do it.


	5. Chapter 5

**Summary for the Chapter:**

> Ryuuji refuses to give in to their situation without a fight, but the search for answers isn't going well. Meanwhile Rin continues to try to make amends for wrongs he doesn't remember committing the only way he knows how—With food.

**Notes for the Chapter:**

> Thanks for all the lovely comments you've all been leaving. I love to hear your feedback!  
> As always, I hope you enjoy!

            Ryuuji slammed the book shut and tossed it on to the pile of other rejects with a frustrated growl. He was ordinarily more delicate with them, but the books that had so far proven to be useless were quickly outnumbering those he had yet to check.

            The pile of books containing relevant information was, as of yet, non-existent and he was beginning to lose patience, but he wasn’t ready to admit defeat. He just wished the one person who shared his secret was not also the one person he’d rather not spend any more time with than he had to; not alone in a dusty old library that got barely any foot traffic anyways.

            He’d spent every evening after class in the private cram school library that week, scouring the shelves for books that talked about their “condition”, and so far the pickings had been very slim. There was very little discussion about demon culture or rituals, let alone their mating habits, outside of combat tactics or information about things that had a direct impact on human life.

            He shelved a book about succubi and incubi—it had only contained a list of mental exercises and precautions one could take to avoid their attacks. There’d been books about other creatures too; Encantado, Lilu and Lilin, Truaco and Popobawa—but they were all demons that were known to rape or seduce their victims before feeding off their life force. There was nothing about the rituals or behaviours used between one demon and another. The closest he’d found was the bite ritual used to turn a human in to a vampire, but that wasn’t the same either. There was no “mutual ownership”, as Mephisto had phrased it, but rather a master/slave relationship. There was also no known cure for that either, except death.

            After everything he’d read he only ended up with more questions. Was he going to become a demon? He hadn’t noticed any other symptoms and had even tested a few anti-demon pharmaceuticals on himself, thankfully with no adverse effects.

            Rin couldn’t control him either, even if his perpetual guilt felt like emotional manipulation at times, but Ryuuji knew the other boy had no more control over how he felt than Ryuuji did, and the link clearly went both ways.

            Ryuuji glanced at the growing pile of rejected books and sighed, rubbing his temples. Time to take a break. He grabbed a stack of books from the reject pile and began to make his way around the library, re-shelving the books, stretching his legs, and giving himself a moment to simply re-think the problem from a new angle.

            Searching the internet was a long shot. It’d be populated with everything from the truth to random crackpot theories and there was no sure way to distinguish fact from fiction.

            There were other exorcist libraries, other schools, even private collections such as the one housed at the Vatican, but he’d need special permission to access those and he had about as much chance of getting it as he did of wishing the vow away on a shooting star.

            He stood on the tips of his toes as he tried to put a book away on the top shelf, but flinched, almost dropping the book as he sensed Rin’s sudden approach—a perk, he’d discovered, of their new found relationship.

            He fumbled for the book, catching it before it could hit the ground and then quickly put it away after a surreptitious glance to see if anyone else was around. There was nobody. The library was as still as a mausoleum and he hadn’t seen anyone else in close to an hour either. A cold sweat rushed over his body as he replayed a mental map of the building through his mind, only to realize he was trapped. He hadn’t realized how empty and still the library was until just then.

            A few moments later Rin’s voice came from across the library, shattering the silence as he called Ryuuji’s name.

            Ryuuji hesitated and took a deep breath, saying a quick mantra to calm his nerves. His heart was still hammering from his initial fight or flight response, but he was pretty sure that Rin didn’t need to call out; that he could sense Ryuuji the same way he could sense Rin, if not better. Rin was a half demon, and he’d sensed strange things before. This might not have been that new to him.

            To Ryuuji this signified two things.

            That Rin could have easily found him if he really wanted to, even if he hadn’t called back, and that by calling for him at all he was basically asking Ryuuji’s permission to approach him. If Rin knew he was there and he didn’t call back, it would be a pretty clear indication that he didn’t want to be found.

            Deep down, Ryuuji knew Rin would respect that. Rin hadn’t approached him at all outside of class since they’d found out about their link, at least not until now. In fact he was pretty sure Rin had been going out of his way to avoid him, so he didn’t have to worry about it.

            He was still on edge, still alert, but he knew Rin could feel it and in turn Ryuuji could feel just how desperate Rin was to fix things between them, yet not push any boundaries for fear of breaking them. Admittedly part of the desperation came from a healthy dose of self-loathing, but he was willing to let Ryuuji set the pace even if it pained him, and pain him it did.

            Ryuuji could feel it then and there, the guilt weighing on him, growing heavier as the silence and the seconds ticked by, but Ryuuji didn’t want to drag this out any longer than he had to either. He just wished his instincts and feelings would learn what his logical mind already knew—that Rin wouldn’t hurt him. He wouldn’t. He had to believe it, because things _had_ to get better between them.

            He didn’t want to go on like this.

            Ryuuji returned to the table he’d previously been sitting at, but remained standing so he didn’t feel defenseless or immobile, even if it was an unnecessary precaution.

            He swallowed his apprehension and called back.

            “O-Over here.”

            The guilt instantly dulled down to background noise once more and Rin peaked out from around the corner.

            “Ah! There you are,” he said, forcing a smile as he scurried over, carrying a small bundle wrapped in cloth. He stopped a few feet short of the table, keeping a respectful distance, and held out the package. “I brought you dinner.”

            “…You didn’t have to.”

            “I wanted to,” Rin said, rolling his eyes as if he expected the rejection, “You’ve been working late every night and I doubt you’re eating properly. Besides, it’s the least I can do.”

            The comment was oddly enough not laced with the tinge of guilt Ryuuji would have expected. It was still there of course—it was always there—but deep beneath it, wrapped up in its core, Ryuuji thought he could sense something else; almost comfortable like a smooth stone warmed by a fire and held in gloved hands on a cold winter’s day.

            “It really is the least I can do,” Rin said softly, probably sensing Ryuuji’s apprehension, “I wish I could help you research, but then…” He shrugged, “We both know I’m no good at that,” he said with a depreciative chuckle.

            Ryuuji nodded, but perhaps the offer wasn’t wholly unwelcome.

            Spending his evenings in the library was lonely, and the research was very slow going.

            With no further refusal coming, Rin approached the table slowly and very obviously made sure to stand on the other side of it, keeping it between them as he pushed a stack of books aside and plunked the wrapped bundle down. He then sat down and gestured for Ryuuji to do the same.

            Ryuuji stood awkwardly at the edge of the table, his hands itching with uncertainty, but then Rin unwrapped the bundle to reveal a three tiered bento box. The smell hit him and Ryuuji’s stomach growled fiercely, reminding him that it had probably been hours since he’d last eaten—during lunch, and then he’d gone straight to the library after cram school.

            Rin smiled knowingly and gestured for him to sit again.

            Ryuuji scoffed. Could Rin feel how hungry he was? Mephisto said that pain would be shared across the link. Did that extend to general discomfort?

            He took a seat opposite Rin and pulled the bento box forward. It was warm to the touch and his mouth watered at the enticing aroma, but there was no way Rin had made it all just for him. It was definitely a meal for two people, at the very least.

            He glanced up hesitantly and found Rin watching him from the corner of his eye, trying to pretend like he wasn’t staring, that he was looking at something infinitely more interesting across the library, but he was doing a piss poor job of it. Ryuuji didn’t need to feel the nervous anticipation to know that Rin was waiting for some kind of sign of approval; whether towards his cooking or the fact that he’d clearly made the meal to share, Ryuuji wasn’t certain, but first he wanted to try something.

            He wasn’t conscious of Rin’s presence all the time, but the feeling always seemed to pop when Rin was approaching him. It always gave him a little start when it happened— made his stomach drop and set his heart pounding just to know that Rin was near—but with the way Rin was clearly keeping his distance he had to question whether or not it was instinctive, or if the other boy was somehow doing it on purpose.

            Ryuuji lifted the lid off the top of the box and then unstacked the tiers, struggling to keep his face impassive. It was practically a three course meal in a lunch box and it hosted a startling variety of foods. He didn’t even have to feign amazement, but he focused on the feeling itself, on really experiencing it instead of just passively letting it slip away. He held on to that feeling and pushed, only for a big giddy smile to break out over Rin’s face. The half demon bounced in his seat as if Ryuuji _had_ complimented him directly. He stilled when he noticed Ryuuji watching him, but he couldn’t supress his smile or the glowing feeling of success that radiated off of him.

            Ryuuji could definitely share in that sense of accomplishment, and he smirked to himself as he reached for a pair of chopsticks, only to pause. Rin had packed two sets after all.

            “Sorry,” Rin said, clearly sensing his apprehension. “Should I…?”

            Ryuuji grabbed the second set of chopsticks and tossed it to him.

            “Just stay,” Ryuuji said, battling down his own apprehension. He pulled a piece of sausage from the box and popped it in to his mouth only to have to hold back a groan. It was juicy and perfectly seasoned, and it simultaneously reminded him of just how hungry he was while also making him excited to fix that.

            Rin visibly relaxed, his smile returning as the tension between them eased, and he leaned back, relaxing as he started to eat. Ryuuji would have done the same except that strange feeling from before was now dancing in his stomach like butterflies. He found himself staring at Rin, eyeing him across the table, but when Rin looked up and met his eyes the feeling dulled, overtaken by guilt once more as Rin glanced away.

            If he looked for it the feeling was still there, but it was obscured, like a statue in the dark back corner of a garden, overgrown with tangling vines. Ryuuji tried to reach for it, to get a handle on exactly what Rin was feeling, but when heat rose on his cheeks he found himself stuffing more food in to his mouth to cover up the awkward lapse instead.

            It no longer felt warm, but rather… uncomfortable. It made him feel oddly sad and he wasn’t quite sure why.

            He shook his head and shoved more food in to his mouth, pushing the feeling down, blocking it out, and trying to ground himself in what he was feeling personally, focusing on the here and now, on what was simply before him; Rin doing his best to make amends with offerings of food and friendship.

            “So…” Rin finally said, trying to break the uncomfortable silence that weighed down on both of them, “Have you found anything yet?”

            “No,” he admitted, grumbling around a mouthful of food, “Nothing. Not a single thing.”

            “Mephisto wasn’t lying?”

            “No,” Ryuuji sighed, “I didn’t think he was necessarily lying, per se, but maybe there was something he doesn’t know? But I wouldn’t put it past him to leave things out as it suited him or spin the truth somehow to manipulate us either, but…” His shoulders sagged and he set the chopsticks down, “I guess I just didn’t want to believe it. Not at least without checking myself, but I’ve been through almost every book that looked like it might contain something relevant, and so far? Nothing.”

            “So… Now what?” Rin asked.

            Ryuuji shook his head, at a loss. “I keep looking. In the meantime we keep our heads down and try to live with the situation.”

            Rin nodded. “Lemme’ know if there’s anything I can help with.”

            Ryuuji raised an eyebrow, glaring at Rin even as he gestured to the stack of untouched books still piled on the table.

            Rin groaned and let his forehead fall against the table as he chuckled.

            “I meant cooking, but fine. I’ll help with this.”

 

 

**Notes for the Chapter:**

> This chapter of Case Studies is brought to you by VineTabris （´ω｀人）~♥  
> Thanks for supporting me.


	6. Chapter 6

**Summary for the Chapter:**

> Ryuuji would like to think he's making progress despite the fact that he can't completely shake the anxiety... and the guilt. Regularly scheduled "hang outs" with Rin help him no longer feel like a cornered animal, but he can't help but feel woefully unprepared when their first mission since the "incident" tests the limits of their bond in the worst way possible.

            A light breeze rustled the curtains, catching the first few rays of morning sunlight as birds chirped and twittered outside his window. Ryuuji’s hand shook as he wiped the sweat from his brow and stared unseeing at the ceiling. Vague memories of Rin—his touch on his skin, his taste on his tongue—still played out in his mind as his heart stuttered in his chest, leaving nothing but an aching void behind.

            Ryuuji groaned as he pushed himself up and out of bed, rubbing his eyes. The dreams were becoming a frustratingly regular occurrence. He wanted to call them nightmares, but the fact of the matter was that they didn’t scare him, not even for a second. He supposed they were better than nightmares. They didn’t keep him awake or haunt his sleep. Rather it was only once he was awake that they left him feeling frustrated, hollow, and sick, and they reminded him of the guilt—not Rin’s guilt, but his own. The same guilt he’d felt immediately after the incident when he’d asked himself why he hadn’t stopped it from happening.

            He didn’t want to admit it, but he couldn’t deny there was some part of him that had been aroused. Before he’d realized what was happening he thought he’d been the one potentially poised to take advantage of Rin. He’d been the one who’d been painfully sober for the majority of what had happened and it hurt—feeling betrayed by his own body.

            Above all else, the dreams served as yet another fucked up reminder about how confused he felt, and that, yes, this was still his life. There was no escaping it, even in sleep.

            He made his way to the bathroom and stared himself down in the mirror, ignoring the dark circles under his eyes as he washed his face. For a moment he just stood there, trying not to bemoan the start of another day. It was time for his run, and as much as he still wanted to just crawl back in to bed and hide, he would stick to his normal routine. It helped. It helped him pretend that nothing had changed even when it felt like everything had. As long as it _looked_ like nothing had changed, nobody would ask any questions.

            He would go on his run, he would go to class, he would eat lunch with Shima and Konekomaru, and he would go to cram school like everything was normal, until it all felt normal. Until it _was_ normal.

            That was the plan anyways, and everything was going smoothly. He got through his classes without getting too distracted by his own thoughts and Rin was still thankfully giving him a wide berth, however, when it came time for cram school Yukio strode in to the classroom and told them they were going on a training mission—their first mission since “the incident”.

            Ryuuji could only sigh and try to repress his rising apprehension as they all prepared to leave.

 

* * *

 

            They loitered in front of the entrance to MephyLand as Yukio spoke on his phone, finalizing the last few details of the mission. Ryuuji stood with Konekomaru and Shima, but idly watched Rin out of the corner of his eye as the other boy stood, shielding his eyes from the sun as he stared up at the imposing statue of their headmaster.

            He had proven to be about as much help with the research as they both thought he would be. His attention span was almost a hindrance, but Ryuuji had to reluctantly admit that the meals and the company, in spite of who it was, were nice. The cram school library was quiet on the best of days, but it was downright dead in the evenings, and more than a little creepy. Rin’s presence livened up their surroundings, and once again… it was helping. It was like a scheduled playdate. Ryuuji could mentally prepare for the visits much better when he knew about them in advance. Rin’s cooking was nothing to sneeze at either, and it added a little luxury to a life grown increasingly depressing.

            Not to mention he made a convenient cover.

            Ryuuji had been making excuses for why he was slipping away to the library without telling anyone what he was doing, but now he could say he was helping Rin study. He might as well have been. They certainly weren’t making any important discoveries; a week had passed and they were no closer to finding a cure for their “condition”.

            That didn’t mean he was totally comfortable with Rin yet—he wasn’t sure he’d ever be—but that was why he watched him now. They had discovered some things about the bond on their own, but they weren’t going out of their way to test it—especially not the more dangerous aspects—which is why he was now on edge, watching Rin out of the corner of his eyes as they all stood waiting to hear the details of the mission.

 

            “MephyLand again?” Rin asked with disdain, his arms crossed over his chest, “This better not be another babysitting mission.”

            “This time it’s serious,” Yukio said as he pocketed his phone, “We’re not just dealing with a prankster. Three people have been hospitalized.”

            A hush fell over the students as they waited for Yukio to elaborate, some of them sharing a look of nervous trepidation. Yukio retrieved a map of the park from a nearby tourist booth and spread it out as they crowded around.

            “The incidents happened here,” he said, pointing to three spots on the map; a women’s washroom on the east side of the park, a body painting parlour, and the hall of mirrors.

            “What happened to the victims?” Konekomaru asked.

            “They’re all in a coma, but there are no physical signs of harm,” Yukio said, “They were simply found unconscious at those locations, so we’ll be splitting in to groups to check them out.”

            “I volunteer to check out the women’s bathroom!” Shima raised his hand.

            “Are you dense?” Ryuuji asked, glaring at him, “What the hell are you hoping to find in an amusement park bathroom, especially when there’s nobody else here?”

            “You never know,” Shima said with a shrug and a wink.

            Izumo rolled her eyes. “If you knew what it was really like, you’d be singing a different tune.”

            Shima raised an eyebrow at that comment, but didn’t have time to question it as Yukio spoke up.

            “That’s fine. Shima-san and Miwa-san can check out the bathroom. Suguro-san and Kamiki-san will check out the body painting parlour. Okumura-kun, Moriyama-san, and Takara-san can go as a three man group to search the hall of mirrors since it covers more ground and will be trickier to search. I’ll be waiting here for your return, and remember, this is reconnaissance work first and foremost. Report your findings to me and do not engage unless you have to”

            The words hadn’t even finished leaving Yukio’s mouth before Ryuuji felt a twinge of concern from Rin. The half demon opened his mouth, but Ryuuji shot him a glare and shook his head, knowing exactly what he’d been about to suggest. The guilt flared up and Rin wilted slightly, but shut his mouth.

            They hadn’t discussed it, but they were both thinking the same thing. The vow linked their lives. Ryuuji was a human and therefor automatically more fragile, but that didn’t mean he was going to let Rin act like his god damn babysitter. He didn’t need his help. If anything, Rin was the one who had to learn not to jump headfirst in to danger, behaving as if his life didn’t matter. Now that he was risking Ryuuji’s life too, maybe that would change.

 

            From there they split up, their groups heading in opposite directions. Izumo and Ryuuji were both silent, all business as they made their way north, to the body painting parlour where guests could pay to receive intricate hand painted body art or face paintings.

            Much like last time, the amusement park had an eerie abandoned feel to it while it sat silent and devoid of life; as if it had been there forever and would go on existing even without the aid or use of humans. That could have had something to do with Mephisto himself, but it could just as easily have been because an amusement park was never designed to be empty.

            The wind whistled through the empty streets, rustling stray bits of garbage missed by the night time cleaning crew while the rides and other attractions loomed silently over them.

            “Did you see that?” Izumo asked.

            Ryuuji stopped and turned, following Izumo’s gaze but seeing nothing but abandoned game stalls.

            “What?”

            “I saw something,” she said, “Over there.”

            Ryuuji said a quick prayer of protection while Izumo summoned Uke and Mike and they all slowly approached the game stall.

            Plastic ducks bobbed listlessly on the surface of the silent water contained in a small pool sitting in the center of the stall. Fake fishing rods with magnets attached to the end of their lines were hung up behind the counter. There was nothing else

            Uke and Mike hopped up on to the counter, then down behind it, sniffing as they went. After circling the stall interior a few times they hopped back up.

            “We sense nothing,” Uke said, his voice filled with disdain.

            Izumo bristled.

            “I _saw_ something moving,” she said again.

            “Maybe you saw the ducks bobbing in the water, or a reflection or something,” Ryuuji said.

            “I wouldn’t jump at a damn reflection,” Izumo snapped.

            Ryuuji put his hands up, putting some distance between them in an effort to stop a fight before it could start only to feel a twinge of concern from Rin. He shot annoyance back. Let him chew on that.

            “That may be the case, Mistress,” Mike said, stepping to Izumo’s side, “But there is nothing here now.”

            Izumo fumed silently for a moment, glancing suspiciously back at the stall, then resumed a stiff march towards the body painting parlour. Ryuuji and the two byakko followed, happy to get back to the case at hand.

            When they finally arrived they approached it much the same way they had approached the last kiosk. Ryuuji said a prayer of protection and the Byakko led the way, sniffing about for signs of evil intent.

            “Nothing,” Uke said after a quick inspection.

            Ryuuji and Izumo shared a glance, then proceeded to inspect the stall themselves.

            The stall boasted examples of artwork and designs customers could choose from, even a few photographs of smiling children showing off their face paint; a few tigers, a few faeries, some Pokémon, and superheroes. Pretty typical stuff.

            The drawers beneath the counter contained face paint and other makeup and accessories, and even a few catalogues of those fake rub-on tattoos people could purchase if they were in too much of a hurry to sit and be painted.

            Ryuuji flipped through the catalogues, looking for anything suspicious—maybe a summoning circle an unsuspecting artist had pulled off the internet without knowing what it meant, or some other type of demonic symbol or incantation.

            Izumo had her byakko inspect the paints, smelling them to see if they contained anything potentially harmful, though if that were the case it probably would have shown up on the hospital toxicology reports. Besides that, there was no mention of the other two victims being painted. It was a long shot.

            “Well, this feels like a pretty big waste of time,” Izumo said as she finished checking the physical stall itself to see if anyone had marked it or somehow cursed it while Ryuuji checked through the various makeup accessories and brushes.

            He shrugged, turning a compact mirror over in his hand as he turned to face Izumo, but he stopped at the last second, glancing over his shoulder instead. He looked back at the mirror. His own reflection looked back impassively, wearing the usual scowl he’d almost come to hate.

            He’d thought he’d seen something in the reflection, but there was nothing there now.

            He put the mirror away with the other makeup accessories under the counter, closing the cupboard.

            “Doesn’t hurt to be thorough,” he said as he stood, “Maybe the others will have found something, but at least we can say for certain there isn’t anything here.”

            Izumo rolled her eyes, though Ryuuji had no idea what he’d done to warrant it. At least she wasn’t sniping at him.

            They finished cleaning up the stall, making sure they’d put everything back where they’d found it, and then started back towards Yukio’s position, taking a different route so they could cover more ground. The byakko griped about having their time wasted, but Izumo firmly ignored them and kept them out just on the off chance they’d be needed.

            They were walking past the fun house when Uke stopped, his hackles rising.

            “It’s nearby. I feel it.”

            “Where?” Izumo asked.

            She and Ryuuji stopped, positioning themselves back to back so nothing could sneak up on them. Ryuuji kept his hands up, ready to reinforce the protection charm if need be.

            “I’m… not sure, mistress,” Uke said after a moment of hesitation. “I can feel it watching us, but can’t sense where it is. It’s like it’s here, but also… somewhere else at the same time.”

            Ryuuji could sense concern coming down the link again, but he ignored it, scanning their surroundings for any signs of incoming attack, when he saw it.

            “There.”

            The mirrors lining the entrance to the funhouse were warped, and he almost hadn’t seen it while they were moving. Their reflections had curved and stretched rapidly over the uneven surfaces while they were walking by, but now that they were standing still, eyes peeled for signs of danger, it was obvious. The reflections in the mirror were not moving with them. The faces were distorted, more so than the warped surface of the mirror called for, and they appeared to be reaching out, scrabbling against the inside surface of the mirror, trying to reach through, to escape.

            And then it stopped, the reflections returning to normal.

            A silent heartbeat passed between them as they stood, still on guard, their adrenaline flaring, and then the moment of panic passed.

            “It’s gone,” Uke said finally, and they all breathed a sigh of relief as the tension eased out of them ever so slightly.

            “There was a mirror at the face painting booth too. That’s probably what links all three locations,” Izumo said, “We need to call Okumura Sensei.”

            Ryuuji nodded as Izumo pulled out her phone, glancing around with dawning realization. Most of the stalls sported anti-theft mirrors, tucked up under the awning of the booth so a single attendant could keep track of their surroundings. The park was covered in shiny metal surfaces to help catch and reflect light when the park came to life.

            They were surrounded by mirrors.

            Ryuuji tensed as surprise came down the link from Rin, the only warning before his body felt like it had been hit by a truck before being sliced by a hail of daggers. The shock of the pain took his breath away and he stumbled. Izumo turned to stare at him, her phone held limply to the side of her face as Ryuuji struggled to remain on his feet.

            “Are you okay?”

            He sucked in a breath as the shock passed and shakily turned his arms over, examining them. He’d almost expected blood, but there was nothing. It was only in his head. There was no physical damage, just intense searing pain, though it was already passing. He still didn’t know exactly how it worked though—how it could kill him.

            “Y-yes,” he choked out, “Rin… The Hall of Mirrors. It’s there,”

            “H-How do you know?” Izumo asked, but Ryuuji didn’t answer. He just started running. With no other choice, Izumo and the two byakko followed, even as she finished calling Yukio, shouting out what they’d discovered over the phone.

**Notes for the Chapter:**

> This chapter of Case Studies in Demon Mating Habits is brought to you by VineTabris, [Jaiden](http://jaidenwriteswords.tumblr.com), Senem, and Angerawr. Thank you so much for your support. (´∀｀人)  
> 


	7. Chapter 7

**Summary for the Chapter:**

> Ryuuji rushes headlong in to danger to make sure Rin is okay, but is it just to make sure Rin doesn't get them both killed through his usual reckless behaviour? And who is really saving who?

            As they approached the hall they could hear shouting and the sound of breaking glass, over and over, thousands of tiny shards splintering to the ground in waves. Ryuuji entered the hall first and almost immediately came face to face with his own reflection. Except it wasn’t really him that stared back out of the mirror. His face was distorted and it smiled at him as its arms stretched forward, breaching the surface of the glass and reaching towards him. He reacted instinctively, driving his elbow in to the surface of the mirror and shattering it even as pain shot up his arm.

            And then he was surrounded. Multiple sinister faces leered at him from the mirrors around him, their smiles drawn unnaturally long and their eyes wide and empty of everything besides an unnatural bottomless hunger.

            Uke and Mike charged forward, striking a mirror each and cleaving them clean in half to fall and shatter against the ground. Izumo drove her heel in to another next to Ryuuji’s shoulder and he flinched away from the high kick as shards of glass rained down around them.

            “Idiot! Were you even thinking?” she shouted at him.

            Ryuuji flushed. He hadn’t been. He’d been hell-bent on getting to Rin’s side, though he wanted to believe it was to stop the half demon from doing something too reckless, from adding to the shared pain he already felt.

            Another series of crashes sounded from somewhere inside the building and Ryuuji put himself between Izumo and the rest of the mirrors.

            “ _I’m_ not the one who needs saving,” she said snidely as she pushed past him, “Arias stay in the back.”

            She directed Uke and Mike forward and then stopped in the entrance as she cast one last glare over her shoulder. “Well?” she asked expectantly, “We obviously can’t just keep smashing mirrors indiscriminately. Use that fat head of yours to figure something out.”

            Fittingly, her words made him want to put his fist through a mirror, but there weren’t any unbroken nearby and his arm already ached from the first mirror he’d hit, so he bit his tongue and silently seethed as she stalked away. This wasn’t the time for fighting anyway.

            Ryuuji pulled out his phone and shot off a quick text to Shima and Konekomaru, to make sure they knew what was going on, and then tried to think of some sort of strategy. As much as it pained him to take orders from her, Izumo was right; they couldn’t just keep smashing mirrors.

            He’d read about demons being trapped in mirrors before. In those instances the demon was restricted to a single mirror, as if the object itself was a cursed prison. In those cases smashing the mirror was actually the last thing you wanted to do because it released the demon in to the human world, which is where the superstition about seven years of bad luck came from.

            The other option was that the mirrors themselves had become portals to Gehenna. The barrier between both worlds was tenuous at best sometimes, and both mirrors and photographs served as distorted reflections of reality, creating the potential for the creation of a gateway between worlds which is why they were sometimes used to summon ghosts or demons and were frequently featured in urban legends. The odds of every single mirror in the park becoming a viable gateway between Gehenna and Assiah however were incredibly slim, unless the demon was just that strong—strong enough to force his way through indiscriminately—but then again, this was Mephisto’s park. He’d orchestrated weirder events and this wouldn’t be the first or even second instance of paranormal activity in the area. Ryuuji also just really hoped the demon’s range of mobility _was_ restricted to the park. If not, there was almost no chance of them catching it.

            But this theory also explained the victims’ comas. If the demon was taking their souls across the gate without killing them it would leave the body relatively unharmed, but empty as long as the soul remained intact. That meant that as far as they knew the demon hadn’t yet done anything with the souls he’d collected. The theory also left them with very few options. If the demon was attacking from Gehenna, pulling people’s souls straight to hell, fatal verses and exorcisms would be useless. All they did was destroy a demon’s earthly manifestation, sending them _back_ to Gehenna. They couldn’t kill it for good unless they could reach the heart, and what was the use of destroying the body if it could cross back over immediately?

            Best case scenario: they would have to destroy, or purify all the mirrors in the park, locking the gates so nothing could cross over.

            Shit.

            The missing souls.

            Ryuuji ground his teeth as another crash came from inside the building and mentally cursed. His friends were still trapped inside within easy grasp of the demon, but breaking all the mirrors was a _very_ bad idea.

            He searched his surroundings for something to use as a weapon, anything at all he could use to defend himself so he could run inside and help the others—explain what he’d reasoned out—but nothing jumped out at him.

            Damn it, he didn’t have time for this.

            He charged in to the building, entering a hall of shattered mirrors and broken, empty metal frames. He could hear the others shouting nearby, but the layout of the hall prevented him from being able to tell which direction the shouts were coming from. He raised his hands to his mouth and called out to them, but the smashing continued, his voice unable to carry over the noise.

            Shards of glass crunched under foot as Ryuuji continued down the path until he came to a fork. He listened to the chaos of noise around him, trying to pick out its source, then chose a path that looked like it would bring him closer to his team mates only to meet a dead end. He backtracked and chose the other path, but that one seemed to take him away from the noise only to loop around to another fork.

            Damnit, shouldn’t a hall of mirrors be easier to navigate when it had _no_ mirrors?

            He picked a path at random this time and charged ahead, realizing he’d made a serious mistake when he rounded another corner and was suddenly surrounded by unbroken mirrors. He’d found a path no one else had taken and a mass of arms reached towards him. Ryuuji ducked under one arm as he tried to back pedal, but he wasn’t fast enough and one of them snagged the sleeve of his shirt. His stomach dropped and he started to struggle as the group of reflections grabbed him, dragging him closer to his own sinister smiling face. He shattered one of the mirrors with a quick left hook, drops of blood falling from the split skin on his knuckles and blossoming like flowers amid shards of glass. He shattered a second with his elbow as they dragged him closer, attempting to work together to pin his arms and then, unable to do much else he head-butted one of the mirrors and saw stars, his vision swimming momentarily. When he shook off the shock his gut sank. He’d barely cracked the mirror. His reflection reached for him again and Ryuuji’s adrenaline spiked as he started to panic, only for the demon’s hands to meet the inside surface of the mirror and stop. Ryuuji blinked. The demonic reflection did not share his confusion. Instead it started pounding its fists against the inside surface, silently shouting its rage on the other side of the damaged barrier and a momentary spark of hope flared in him. It couldn’t bypass the crack. The mirror was far from shattered, but the cracked surface prevented the demon from reaching through.

            But that was only one down.

            Two mirrors remained and despite his struggle his face was forced up against the cold hard glass. A stab of fear gripped Ryuuji’s gut as his body grew cold and numb. It was like trying to swim in arctic waters and his body was shutting down, growing heavier and heavier as something pulled at him, stretching him too thin. He couldn’t call out, couldn’t move, couldn’t –

            The mirrors around him shattered in to a hail of broken glass and blue flame and Ryuuji sucked in a breath like it was his first. The demon’s grip on him failed and Rin caught him as he fell, dragging Ryuuji’s arm around his shoulder to support his weight

            Ryuuji stared up at Rin, the flame that licked across his body surrounding him in a halo of blue fire, and for a moment time seemed to crawl before Ryuuji’s senses clawed their way back to him.

            Rin’s clothes were slashed to ribbons and he was covered in streaks of blood from a thousand tiny superficial cuts. He looked like he’d gone _through_ a mirror. Or two. That explained the pain.

            “Are you okay?” Rin asked, peering down at him, his irises flickering with demonic fire and his fangs just inches from Ryuuji’s face.

            Ryuuji became startlingly aware of just how close Rin was and choked back his fear as he nodded, struggling to stand, to support his own weight and put some space between them.

            “Are you sure?” Rin grabbed Ryuuji’s hand, turning it over and noting the bloody knuckles, then drew his sleeve up to try to examine his elbow and Ryuuji recoiled, slapping his hand away.

            “I-I’m fine!” Ryuuji said, his voice cracking.

            An odd jumble of emotions came from the other boy—confusion, annoyance, restrained hurt centering on worry that had only been met with anger, and a renewed surge of guilt that had almost become familiar—but it was all distinctly Rin, and aside from a hint of annoyance his face remained impassive, a light scowl marring his features, but otherwise offering no hint of the hurt Ryuuji could feel rolling off of him.

            After a moment Rin snorted. He looked like he wanted to say something, but instead he turned to leave, his sword drawn and at the ready as he prepared to leap back in to the fight.

            “Wait!” Ryuuji said, remembering why he’d entered the hall in the first place, “We need to get everyone out of here.”

            “I got it covered. As long as you stay close I won’t have to worry about you getting hurt again.”

            Ryuuji bristled. “That’s not it! We have to stop breaking mirrors! If we break them all the souls of the previous three victims will likely be trapped in hell forever.”

            Rin’s eyes widened before a sobering look crossed his face.

            “Got it,” he nodded. “I’ll get the others. You okay to get out on your own?”

            “Yes,” Ryuuji bit out, his voice flat with restrained annoyance.

            Rin gave him one last glance before nodding, and then took off through the hole he’d made in the path, heading straight for the rest of the fight.

            Ryuuji took a deep breath to reign in his anger and then turned, following the exact path he’d taken to get back to the entrance to the hall and found the amusement park already swarming with senior exorcists. It was a jarring contrast to find the park now filled with people, running about and shouting orders when it had been deserted just moments before.

            Ryuuji spotted Yukio a few yards off amid the chaos and headed towards him, flagging him down.

            “It’s in the mirrors,” Ryuuji said as soon as he was within earshot of the young teacher.

            Yukio nodded at him. “Yes, Kamiki-san explained the situation to me on the phone. I’ve called in a full investigative squad to sweep the park and close all the portals since it would be an impossible task for such a small team to handle reliably.”

            “Are there any plans for rescuing the souls of the victims? I think if we keep some of the warped mirrors intact we can restrict the demon to a handful of portals. It doesn’t seem to be able to attack from a mirror with a damaged surface.”

            “Good to know,” Yukio said, shooting off a quick text on his phone. He didn’t say anything more.

            Ryuuji hesitated. “Do you need me anywhere?”

            Yukio shook his head. “The most efficient method of sweeping the park is still being determined. Are the others still inside?”

            “Yeah, but I’ve told them what I know. They should be on their way out.” He then glanced around quickly. “Actually Shima and Neko never made it over here. Have you seen them?”

            Yukio shook his head and Ryuuji cursed under his breath. He’d sent them that text but hadn’t waited to see if they responded, or if it had even been marked as read. What if the demon had gotten to them first and nobody had noticed?

            He whipped his phone out, the sun high in his sky illuminating the smooth black screen from behind his head. He glowered down at the phone, his brow creased with worry.

            And his reflection smiled back.

 

* * *

 

            Rin was on his way out of the hall of mirrors with the others when it hit him and he jerked to a stop as shock and fear struck him before immediately being silenced. That same cold, icy feeling from when Ryuuji had been attacked gripped his veins, like a cold, withered hand reaching right inside his body, squeezing his heart.

            And Rin burned.

            Blue fire erupted from the hall of mirrors in a shower of glass and steel to screams of terror from the surrounding exorcists. Many of them drew their weapons, but Rin was oblivious to it all as he leapt to where Ryuuji lay on the ground unconscious, his phone lying beside his prone body.

            Rin whipped around, looking for the danger; the enemy; the thing that had attacked Ryuuji. He then looked down at the phone, drawn only by a strange pull. Instinct took over and Rin dove on it, gripping the phone in a shaking, clawed hand as he knelt over Ryuuji’s body, but all that looked back at him was the reflection of his own snarling face.

_No, no, no! Give him back!_

            His flames surged around him and he chased the feeling that pulled at him even as it weakened, refusing to let it go.

_GIVE HIM BACK._

            The gateway cracked under his will and the world around him vanished, along with his sense of self. He just was. All that was left was fire and feeling—hatred, anger, suffering, agony, despair—and the terrifying sensation that if he could see, smell, or feel his surroundings, he’d regret it.

            And there, at the end of the feeling tugging on him, was Ryuuji, indistinct in form, but immediately recognizable.

            Rin moved forward and something blocked his path. Another presence—arrogance, greed, and a self-satisfaction that turned briefly to doubt the moment Rin pressed against it, as if it recognized him for what he was. The presence wavered, then pushed back.

_He’s mine now._

_GIVE HIM BACK._

_I claimed his soul. He belongs to me._

_GIVE HIM BACK!_

_My prince, I–_

_GIVE ME BACK MY MATE!_

_H-he’s-? I didn’t-_

_GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM BACK! GIVE HIM B—_

            The other presence choked as Rin brought the full weight of his rage to bear down upon it and its fear spiked in one last desperate plea before the world shattered in to darkness, only to be replaced by white, hot blinding light and fire.

 

 

 

**Notes for the Chapter:**

> This chapter of Case Studies in Demon Mating Habits is brought to you by VineTabris, [Jaiden](http://jaidenwriteswords.tumblr.com), Senem, and Angerawr. Thank you so much for your support. (´∀｀人)  
> 


	8. Chapter 8

**Summary for the Chapter:**

> When Ryuuji was in danger, Rin's reaction was purely instinct. Rage and fire and death. But even though that rage was properly directed and Ryuuji is now safe, Rin's outburst happened in front of a large group of humans, and exorcists at that.  
> That has never been a good thing.

**Notes for the Chapter:**

> I'm getting very close to running out of pre-written content on all fronts, so I might be preparing to go on hiatus again soon. At the very least, I'll be putting this story on break soon as I'm doing a 30 day writing challenge on my blog next month so my writing focus is gonna be a bit shifted for a while.  
> As always, thank you for your patience and thanks for reading and commenting. ;w;

            People were shouting. Beneath the dull roar of his own pulse filling his ears Ryuuji could hear them, scrambling about and shouting in a mass of voices that blurred together into an indecipherable cacophony. He recognized the commanding tone of shouted orders and the swift march of feet moving to follow them, but the words were jumbled together, running over one another and made incomprehensible.

            The familiar and unrelenting cadence of the noise pulled him up out of the comfortable haze of warmth that enveloped him. He felt safe, wherever he was, but the shouting was getting louder, becoming impossible to ignore and his head was starting to pound. It was a struggle in and of itself to open his eyes, but reality snapped back to him in a jarring rush of adrenaline when he did.

            He was lying on his back on the ground with Rin crouched over him, snarling at the crowd that circled them. Teeth bared and eyes wild, his flames surged around the both of them, keeping the crowd at bay.

            Ryuuji tried to raise his arm and managed only a slight twitch of his fingers, his body feeling both far away and like a lead weight as it refused him. A second shaking attempt allowed him to lift his arm an inch from the ground before the effort overwhelmed him.

            “… _R-Ri_ … _n.”_

            His throat felt like it hadn’t been used in years and his voice came out in a whispered croak, but Rin’s head snapped down as he looked at him, his hearing too good to miss the soft sound even amid the shouting and the chaos. Rin’s eyes met his and his expression softened to a look of intense, disbelieving relief.

            The flames wavered and snuffed out as Rin scrabbled to get his arms under Ryuuji, lifting him off the ground and pulling him in to a tight hug. Ryuuji lolled in to the embrace, unable to fight it and not even wanting to as Rin clung to him, shaking, the half demon’s emotions crashing over him.

            “Thank god,” Rin said, his voice a soft whisper beside Ryuuji’s cradled head.

            And then they were pulled apart.

            Ryuuji could only watch from where he had fallen as Rin was pushed to the ground, his arms pinned behind his back as a dozen guns simultaneously trained on him and frightened voices ordered him to stay down. A doctor stepped in front of him, blocking his view of Rin, and began to examine him.

            Once again he had no choice but to let it happen. He wanted to push the man out of the way so he could see what was happening to Rin, but he could barely muster the energy to answer his questions, let alone move.

            He could feel it—the strain in his shoulders and the pressure on the center of his back from where someone had their foot planted on Rin, pinning him down. He could feel Rin’s fear and anger, the emotions storming inside of him, ready to boil over yet restrained by a single thread of fear. Ryuuji did not know what he was afraid of. Rin could have easily tossed them aside like ragdolls, but he stayed his hand, allowing them to pin him down—and yet, above it all, Rin was simply relieved.

            He didn’t need some kind of psychic demon bond to sense the fear and panic that permeated the crowd though. Someone was shouting at Rin to stay down even though he wasn’t struggling, and one wrong move, one jumpy trainee or itchy trigger finger and they could all start shooting. Ryuuji tried to calm his own swirling thoughts, put aside the fact that his body was still refusing to respond the way he wanted it to—that the stupid doctor seemed to only be checking him for physical injuries, for burns—and focused instead on being thankful that he was alive at all. That Rin had come for him.

            He hoped that feeling would comfort Rin even as his head was pressed roughly against the ground, his cheek scraping across asphalt.

            “Let me through. He’s one of my students. I’ll handle it from here.”

            Yukio took the place of the other doctor and began to start the examination all over again, taking Ryuuji’s pulse.

            “…It was…the demon…” Ryuuji breathed out. Yukio was shining a penlight in his eyes, checking his autonomic reflexes, but when the words left Ryuuji’s mouth he let the penlight drop.

            “It got your soul?”

            Ryuuji nodded, at least he tried to, and was relieved to feel some of his strength and motor control returning, albeit very slowly.

            Yukio glanced behind them, to the crowd of guards still pinning Rin to the ground.

            “They think he attacked you.”

            “He d-didn’t,” Ryuuji said as he tried to sit up. All he could manage was lifting his head a fraction of an inch from the ground, his arms tensing as he tried and failed to brace them against the ground, to leverage himself upright. The mere attempt winded him and Ryuuji’s vision spun. He tried again. “He-”

            “I know.” Yukio put his hand on Ryuuji’s chest, “Don’t push yourself. If your soul was removed from your body the link will be tenuous at best for the next couple days.”

            “But-”

            “If you push yourself you risk breaking the link between your soul and body again,” Yukio said, his voice firm, like he was speaking to a child. “There’s nothing you can do. Rin bared his flames at humans so all we can do is hope the situation plays out peacefully.”

            As if on cue the crowd of exorcists parted to reveal Arthur, striding forward in his pristine white uniform. It had nary a scratch or speck of dust on it and was completely unmarred by the day’s events. He marched through the crowd with Caliburn resting lazily over his shoulder and came to stop in front of Rin, sneering down at him.

            “Word travels fast,” Yukio said under his breath, and this time he helped Ryuuji sit up so they could both watch the events unfold before them. It was all Ryuuji could do to keep his own head up.

            Arthur lifted Caliburn from his shoulder and hefted the cursed sword as if it weighed nothing, swinging it in a wide arc and pointing it at Rin. An eerie hush fell over the crowd, the silence seemingly even more out of place than before given the massive crowd that surrounded them, gawking like tourists.

            “I knew you’d show your true colors soon enough, Satan spawn,” Arthur said, speaking loud enough for everyone to hear him.

            “I- I didn’t-” was all Rin could get out before his face was shoved back in to the asphalt.

            “Give me one good reason why I shouldn’t put you down right here.”

            Ryuuji’s heart lurched, but to his credit Rin kept his head respectfully bowed even though Ryuuji could feel his annoyance and anger mixing with a cold rising fear. When Arthur had paused long enough to indicate he was actually waiting for an answer, Rin spoke.

            “I didn’t hurt anybody.”

            Arthur scoffed.

            “We’ll let that be decided by the Grigori.”

            He then snapped his fingers and one of the exorcists nearest him produced a pair of ancient looking manacles, handing them off to the exorcists restraining Rin. As soon as he was shackled Arthur grabbed him by the collar of his jacket and hauled him up, putting his sword at his neck as he began to drag him away.

            Rin struggled to keep up with Arthur’s pace in the awkward position, yet still turned to cast one last glance at Ryuuji to make sure he was okay.

            Their eyes met and Ryuuji could feel Rin’s relief as sharp as he felt the blade against his neck.

            And all Ryuuji could do was watch, struggling and failing to see past the doctors as they arrived with a stretcher and loaded him on to it. He was barely able to crane his head as the feeling of Rin’s presence moved further and further away.

            Memories of the next little while were clouded by a soul crushing exhaustion.

            Konekomaru rode with him to the hospital, the bald little monk fussing at his side and fretting over the fact that he hadn’t been there to do his job, despite Ryuuji’s constant wheezing assurances that he was fine.

            But he wasn’t fine. Even though he could already feel a small measure of strength returning, he felt utterly useless. Rin had saved his life and there was a very real risk that the council was going to execute him for his efforts, subsequently executing the both of them without even realizing it. Rin had saved his life, and there was little he could do to return the favor. His body wasn’t listening to him, and neither were the doctors or exorcists who cared for him as he was transported to the hospital. He was trapped.

            He was trapped inside his own body with the nagging memory of what Rin had said—what he had felt—when he’d fought to save Ryuuji’s soul, and now he had all the time in the world to do absolutely nothing other than think about it, until they were both killed.

**Notes for the Chapter:**

> This chapter of Case Studies in Demon Mating Habits is brought to you by VineTabris, [Jaiden](http://jaidenwriteswords.tumblr.com/), Senem, and Angerawr. Thank you so much for your support. (´∀｀人)  
> 


	9. Chapter 9

**Summary for the Chapter:**

> With the events at MephyLand finally over, Ryuuji has a moment to actually stop, think, and process everything that happened. Everything that Rin did and said. It's not long though--far from long enough--before he must give serious thought to giving testimony at Rin's tribunal in an effort to save them both from a swift and merciless execution.

**Notes for the Chapter:**

> One last reminder that my regular writings will be going on hiatus as I'm doing a 30 day kink writing challenge! If you haven't already, you can swing by my [tumblr](http://korrinbelle.tumblr.com) and add your own suggestions to the pile. :9  
> Thanks as always for reading and reviewing!

            Ryuuji’s internal clock woke him early despite the fact that he couldn’t go running—he hadn’t been running in days and it might not have been so bad if he could just go back to sleep, but that was a lost cause. Once reality invaded his thoughts, there was no going back. With nothing much else to do but think and count ceiling tiles Ryuuji took a deep breath and forced himself in to a sitting position. It was getting easier—he could actually move under his own power—but the simple physical activity still winded him.

            After a moment to gather his strength he reached for the crutches that sat leaning against his bed and then hobbled to his feet on weak, shaky legs. Even with the crutches it was hard, and he was barely able to make it to the bathroom not even five feet from his bed.

            Going to the bathroom and then washing your hands on crutches is less than easy, and when he was done Ryuuji begrudgingly went to the wheelchair that had been left for his use. It was what the doctors had initially insisted he use instead of the crutches, but he could be as stubborn and foolhardy as the best of them.

            Damn it.

            He sank down into the chair, the rigid tension he'd been using to keep himself upright slipping out of his body, and after another short rest he wheeled himself out of the room. Using the wheelchair wasn’t any less tiring than the crutches, but at least he was already sitting.

            It was still early and the hospital halls were practically deserted, but he couldn’t stand the thought of lying in bed for a second longer with nothing but his mind to keep him occupied. He’d already done plenty of thinking.

            The memory of his rescue was indistinct and fuzzy, probably a result of not having been in his own body, having no eyes to see or ears to hear, but he’d been conscious of what had happened; of the possessiveness and rage that Rin had felt when his soul had been taken, and the instant relief upon its return.

            That feeling he’d sensed in Rin earlier, the warmth that seeded his guilt; it suddenly all made sense, like a camera lens bringing the world in to focus. Deep down, even if Rin refused to admit it, Ryuuji could feel it. A part of Rin was happy this had happened and that was the source of his guilt. It was eating him alive.

            When he’d first noticed it back in the library Ryuuji had pegged it as friendly affection and simple guilt over the fact that Rin had lost control, even if it had been spurred on by the pheromones, but when the two of them had been nothing but their souls, with no barriers in between them, he’d felt it all, undisguised and raw, an affection and an attraction that was more than friendly—it was possessive and hungering.

            Not to mention Rin’s words pretty much spoke for themselves. Well, they weren’t words per se—one did not need to speak or even hear when one was nothing but spiritual energy—but it was more like intention and meaning. Still… the meaning had been clear.

            “ _GIVE ME BACK MY MATE!”_

            As much as Rin regretted what he’d done, and as much as he refused to admit it, he obviously felt very different about the whole situation than Ryuuji did.

            Damn it, what was he supposed to do with this? He wasn’t sure he’d be able to look at Rin the same way after this.

            Ryuuji kept his face impassive as he passed the night shift nurse sitting at the front desk, giving her a simple nod in greeting and she nodded back, barely paying him any mind as he wheeled himself towards the hospital entrance. Even if she’d been paying much attention she wouldn’t have noticed the turmoil that stormed inside of him.

            Part of him felt betrayed. Was Rin really working as hard as he could to help Ryuuji research a cure? He didn’t want him to be punished—god knows he was punishing himself enough—and he still knew, objectively, that had it not been for the pheromones nothing would have happened, but… Had it influenced things?

            He sighed. Their lives were linked. If Rin was executed… If he died, then Ryuuji would die too. This new information hadn’t changed anything, and yet… Everything felt different. He couldn’t help simply feeling off about it all.

            Should he have blamed Rin? Should he be angry? Should he rail out, shout at him, hit him, and exact his revenge upon him?

            He didn’t know how he was supposed to feel.

            He sighed as he wheeled himself out the front doors and on to the lawn in front of the hospital. The thin hospital gown he was wearing did little to fight off the chill, but he ignored the mild discomfort, taking a deep breath of fresh morning air. Hues of pink and orange danced together, lighting up the clouds from below in a breathtaking array of color as the sun crested the horizon.

            And despite everything that had happened to him, he knew Rin wasn’t fairing any better. In fact he had it much worse. At least Ryuuji was free to enjoy the sunrise. Rin on the other hand had spent all three days locked up in a cell somewhere, or so Ryuuji’d been told. He could feel the bruises where Rin’s restraints dug in to his skin and the stiffness in his joints from being held nearly immobile for days at a time. It was a small mercy, but rather than immediately executing Rin a tribunal had been scheduled to judge the events at the park, and given Ryuuji’s meager recovery he would be able to make an appearance and speak in Rin’s favor. He didn’t have time for doubts. The part of him that felt uncertain about everything had to be locked away and ignored, at least for the time being.

            He’d already gone over everything he could say that might help Rin—three days restricted to a hospital bed gave you a lot of free time to think and worry—and he was not confident.

            Rin had put his own life at risk to save Ryuuji’s and somehow saved the lives of the other victims too—they all woke up shortly after Rin’s battle of wills with the demon—though Ryuuji was fairly certain the council would try to brush that off as a coincidence. And despite what the other exorcists reported seeing—a half demon gone feral—he hadn’t hurt a single person. He’d just…

            He’d been trying to protect Ryuuji, even if it had been fueled by other “motives”.

            The problem was the overreaction. He could brush it off as them being friends or team mates, but the council would most certainly demand a reason for Rin’s fearsome behaviour—a reason that would assure them it was out of character and unlikely to happen again—yet telling them what he knew about that would not make Rin look good either. Telling them about Rin’s personal motives would only lead to further questions—questions that would undoubtedly lead to their bond.

            Ryuuji sighed. The sun crawled higher in the sky, touching his body with its warmth, and the hospital slowly came to life behind him. Other patients joined him on the lawn, stretching tired, injured limbs and going for their own morning walks.

            His stomach growled, but he ignored it for the time being. He’d been very hungry lately, but he was more than happy to chalk it up to being a side effect of his condition. Everything felt like it took so much more energy, perhaps his body was simply burning through the provided fuel that much quicker? But for now, food could wait. He could always eat later, but this… this sunrise might have been his last.

            He sat on the lawn for at least an hour before he wheeled himself back to his room. A nurse stopped by to check his vitals and record his data on a chart. As usual, physically he was fine. He didn’t hurt anywhere. He wasn’t injured. His body just didn’t want to follow orders very well.

            He ate the food they brought him, but still felt hungry. He then spent the better part of a half hour struggling to change out of his hospital gown and in to the clothes he’d wear to Rin’s tribunal. He wasn’t about to ask a nurse for help and it was a school day. He’d insisted Shima and Konekomaru not miss anything on his account, but… That also meant he wouldn’t see them before the tribunal. He was almost glad…He didn’t have to pretend that everything would be fine; that Rin’s life was the only one at risk.

            He spent the rest of the morning writing and re-writing them a letter—just in case it was his last chance to do so—and wishing he’d never kept it all a secret. He had no idea what he could have told them, but it would have been nice having someone to share this burden with and not feeling so alone.

 

            When Mephisto arrived a short time later it was with all the fanfare of a single small puff of purple smoke. He bowed, gesturing with his arm as if to say “after you” and Ryuuji slid in to the wheelchair and grabbed his crutches, laying them across his lap before he wheeled himself towards the door. When he drew up beside him, Mephisto placed a hand delicately on his shoulder and leaned down to speak softly in Ryuuji’s ear, as if someone might overhear them.

            “Have you decided what you’re going to say to the council?” Mephisto asked, his voice ripe with a mocking kind of curiosity, but Ryuuji just scowled. Mephisto’s tone was light and taunting, as if he knew that Ryuuji had gone around and around in circles without making any headway on deciding whether or not he was going to try to concoct an elaborate lie or whether he would tell the truth—the whole truth—because they both knew a simplified version of the truth, the sterilized version, would not cut it.

            “Well, I can’t say I blame you,” Mephisto said as he pulled a key out of one of the many pockets hidden in his outfit, “It’s only your very lives riding on the outcome of this trial.”

            Ryuuji grit his teeth, ignoring the smirk he knew Mephisto was sporting, and waited as he used the key to open the hospital door. He wheeled himself through quickly and the door was shut behind them.

            Ryuuji blinked, glancing around in confusion at their surroundings.

            Far from the intricate stone work and the high vaulted halls of the Vatican that he expected, he found himself in a dimly lit, musty smelling corridor with barred cells lining the walls. He felt Rin’s attention pique like a beacon in the dark and the hair on the back of his neck stood up. He was suddenly very close by.

            “I thought you’d like to speak to him before the tribunal. You might not get a chance to do so afterwards if you’re unable to convince the council of Rin’s good standing,” Mephisto said.

            “Thanks…” Ryuuji said, gritting his teeth as he stared down the corridor. Rin’s words from the other day echoed in his mind again, and he swallowed the lump in his throat, his body growing warm. He hadn’t expected to see him before the trial. He didn’t really want to see him. He didn’t know what he was supposed to say.

            “I’ll wait here,” Mephisto said, as if to remind Ryuuji they were working with borrowed time.

            Ryuuji nodded and started down the hallway, glancing into each cell he passed, but they were all empty save for one.

            Rin’s eyes were down when Ryuuji came in to view, but they widened when he looked up and noticed the wheelchair.

            “Wha– Are you okay?” Rin asked, looking Ryuuji up and down for injury, clearly confused that he couldn’t sense the problem.

            “I’m fine,” Ryuuji said after a moment of stunned silence, his eyes wide and his previous apprehension forgotten the moment he saw Rin, “Forget me. What about you?”

            Rin’s hands were held behind his back, likely still cuffed. A heavy looking iron collar sat around his neck and a short link of chain forced him to kneel on the cold stone floor. Ryuuji could feel it; a deep ache seeping in to his joints, caused by the fact that Rin had been forced to sit motionless for days at a time. And then it hit him.

            “Are they feeding you?” he asked incredulously.

            Rin nodded. “Once a day or so… I think? Not sure how long I’ve been in here.”

            “That’s ridiculous!” Ryuuji grit his teeth and clenched his fists, squeezing the grips on the wheelchair, trying to battle down his outrage.

            “Why the hell are you putting up with this?”

            “It’s not like I got a choice,” Rin snapped, his cheeks coloring and he glared up at Ryuuji before he grit his teeth and looked away. “Anything that happens to me happens to you… So… I’m trying not to have a repeat of last time…” Rin looked down at the floor petulantly, his lips pursed in a hard pout.

            “Oh…”

            Ryuuji hadn’t been there the first time, hadn’t seen it, but he heard about it—about how Angel had cut Rin’s foot off to keep him in line. Yeah, that was definitely something he didn’t want to experience, even by proxy of the bond between them. It was something he didn’t want Rin to have to experience again either, no matter what had happened between them.

            Ryuuji grit his teeth and glowered down at the floor, unable to look at Rin. He was thankful that he was being careful, and yet, in spite of everything that had happened, he hated the thought of him being stuck like this for his sake. Ryuuji almost felt guilty for wishing harm on him at all as Rin sat in the cell, chained up like an animal.

            “Sorry,” Rin said, and Ryuuji glanced up at him quickly.

            “Ya’ ain’t got nothing to be sorry about.”

            “I mean, for dragging you in to all of this.”

            “You saved my life.”

            “No, I mean for everything. Cuz’ I bit you and now we’re here, and I’m dragging you down with me.”

            Ryuuji shrugged. “Not like you did it on purpose.”

            “But it’s my fault!” Rin said, and Ryuuji felt the core of warmth inside Rin flare, the guilt, self-hatred, and loathing flaring with it, stronger than he’d felt it before and washing over him in a sick dark wave. He had to fight the urge to recoil, gritting his teeth as bile rose in his throat.

            “No, it ain’t!” Ryuuji said, more forcefully than he’d intended, “It was cuz’ of the demon. It’s not like you meant for any of this to happen.”

            Rin looked down at the ground, his brows drawn together as pain etched itself across his face.

            “It is my fault,” he said softly, his voice resigned. Then Rin looked up at him, his eyes soft and his cheeks red. He opened his mouth, then closed it, then opened it again and took a deep breath, the warmth inside him pulsing alongside hope and anxiousness and fear, and Ryuuji panicked as he realized what Rin was about to say.

            “I… I like-”

            “Stop!” Ryuuji said, his own cheeks red even as he silenced Rin. “It’s _not_ your fault! You saved me from the demon, now I’m gonna’ do my best to save you, and I’d appreciate it if you could feel even the slightest bit thankful about it so you don’t distract me with your damn pity party.”

            Rin’s mouth was drawn in a hard line and Ryuuji could tell he was struggling to keep his feelings off his face, but he’d never been very good at that. He nodded meekly. A confusing maelstrom of emotions was coming from him, his guilt stronger than ever, but alongside it was a strange sense of resignation and hopelessness.

            Ryuuji sighed, trying not to feel guilty. If he was right about what Rin had been about to say, then his refusal to even listen was an awfully cold rejection, but he didn’t have time to play emotional babysitter, and he didn’t want to hear it. He didn’t have time. Not now.

            “Look,” Ryuuji said after a moment of awkward silence, We’ll talk… later.” He gestured vaguely. No mention of the fact that there might not be a later, but Rin nodded so Ryuuji turned to leave and made his way back to the entrance where Mephisto was waiting for him. The demon headmaster stood patiently, a small smirk resting upon his face, though he said nothing until Ryuuji was by his side.

            “I take it you’re ready to face the lions?”

            Ryuuji took a deep breath and then nodded grimly.

            “I’m sure you don’t need me to say it, but tread lightly. The Grigori will be looking to use anything you say against us.”

            “Us?” Ryuuji asked, furrowing his brow as he glanced up at Mephisto.

            “Demons.”

            “I am not-”

            Mephisto held up a hand, silencing him.

            “As it stands, you’ve basically married in to the family, and, if push comes to shove, I’m sure you’ll find there’s little difference as far as the Grigori is concerned. Our problems are your problems, and I told you, most demons are loathe to enter in to a pact such as yours because it creates a weakness outside of their control.”

            “Are you saying I shouldn’t tell the Grigori about… About me and Rin?” Not that he had planned to.

            “Now, I certainly didn’t say that,” Mephisto said with a laugh as he pulled out a different key, “Just be very considerate of what you say and how you say it.” He unlocked the door and pushed it open, standing aside. He looked down at Ryuuji with a nod, gesturing him forward. “Remember; it’s not necessarily just your lives that are on the line.”

            Ryuuji only had a moment to cast Mephisto a confused glance before he was wheeled through the door.

**Notes for the Chapter:**

> This chapter of Case Studies in Demon Mating Habits is brought to you by VineTabris, [Jaiden](http://jaidenwriteswords.tumblr.com/), Senem, and Angerawr. Thank you so much for your support. (´∀｀人)  
> 


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